Monocarbams

ABSTRACT

The invention relates to compounds of formula (I): 
                         
wherein R 1 , R 2 , R 3 , R 4 , R 5 , and R 6  as defined herein. The invention also relates to pharmaceutical compositions and methods of treating bacterial infections using compounds of formula (I).

This application is a continuation of U.S. patent application Ser. No.12/641,343 filed Dec. 18, 2009, which claims the benefit of U.S.Provisional Patent Application No. 61/139,159 filed Dec. 19, 2008.

FIELD OF THE INVENTION

The present invention relates to Monocarbam compounds and their use asantibacterial agents in animals, including humans. The invention alsorelates to methods of preparing compounds, intermediates useful inpreparing compounds, and pharmaceutical compositions containingcompounds. The present invention further includes methods of treatingdisease, e.g., bacterial infections by administering compounds orcompositions to subjects in need of such treatment.

BACKGROUND OF THE INVENTION

Monocarbams are a class of synthetic monocyclic beta-lactamantibacterial agents which have as their salient feature, a substitutedsulfonylaminocarbonyl activating group at the N-1 position. The earlystudies in this area were conducted by workers at the Squibb Institutefor Medical Research, Cimarusti, C. M. & R. B. Sykes: Monocyclicβ-lactam antibiotics. Med. Res. Rev. 4: 17˜20, 1984. Monocarbams havealso been previously discussed in EP 0281289, published Sep. 7, 1988.These and all documents cited herein are fully incorporated in theirentirety by reference herein.

Although not limiting to the present invention, it is believed thatmonocarbams of the present invention exploit the iron uptake mechanismin bacteria through the use of siderphore-monobactam andsiderphore-monocarbam conjugates. Barbachyn, M. R., Tuominen, T. C.:Synthesis And Structure-Activity Relationships of Monocarbams Leading toU-78608. Journal of Antibiotics Vol. XLIII No. 9: 1199-1203, 1990. Thus,at least in general terms, the activity and mechanism of action ofmonocarbams are generally known, although the present invention is notbound or limited by any theory.

There is a continuing need for new antibiotics, such as monocarbams, inresponse to the increasing emergence of resistant organisms and toimprove safety, among other reasons.

SUMMARY OF THE INVENTION

The present invention relates to certain compounds of formula (I), theirpreparation and useful intermediates, pharmaceutical compositionsthereof, and methods of treating and preventing bacterial infectionstherewith. In many embodiments, the compounds are active and effectiveagainst organisms that are resistant to other antibiotics.

In particular, the present invention relates to a compound of formula(I):

or pharmaceutically acceptable salt thereof; wherein

R¹ is (C₁-C₆)alkyl substituted with 1 to 3 substituents selected fromthe group consisting of halo, hydroxy, (C₁-C₆)alkoxy, —NR⁷R⁸,—C(═O)NR⁷R⁸, and a 3 to 7 membered heterocycle, wherein R⁷ and R⁸ areindependently hydrogen or (C₁-C₆)alkyl, wherein said heterocyclecontains 1 to 3 heteroatoms independently selected from O, N, or S;

R² is hydrogen or methyl;

R³ is hydrogen or methyl;

R⁴ is hydrogen, deuterium, or methyl optionally substituted with 1 to 3substituents independently selected from F or Cl;

R⁵ is hydrogen, deuterium or methyl optionally substituted with 1 to 3substituents independently selected from F or Cl;

R⁶ is H or —C(═O)OH; and

X is C(H), C(F), C(Cl), or N.

In one embodiment, the compound of formula (I) has the formula (IA):

or pharmaceutically acceptable salt thereof. In one embodiment R⁴ ismethyl optionally substituted with 1 to 3 substituents selected from For Cl. In another embodiment R⁴ is hydrogen. In another embodiment R⁵ ismethyl optionally substituted with 1 to 3 substituents selected from For Cl. In another embodiment R⁵ is hydrogen. In another embodiment R⁶ is—C(═O)OH. In another embodiment R⁶ is hydrogen. In another embodiment Xis C(F). In another embodiment X is C(H).

In another embodiment X is C(Cl). In another embodiment X is N. Inanother embodiment R² is hydrogen. In another embodiment R² is methyl.In another embodiment R³ is hydrogen. In another embodiment R³ ismethyl.

In yet another embodiment, R² is hydrogen; R³ is hydrogen; R⁴ is methyl;R⁵ is methyl; R⁶ is —C(═O)OH; and X is C(H). In another embodiment,additionally R¹ is (C₁-C₆)alkyl substituted with 1 to 3 substituentsselected from the group consisting of halo, hydroxy, —NH₂, —C(═O)NH₂,and a 3 to 7 membered heterocycle, wherein said heterocycle contains 1to 3 heteroatoms independently selected from O, N, or S. Alternatively,in another embodiment, R¹ is (C₁-C₆)alkyl substituted with 1 to 3 halo.Alternatively, in another embodiment, R¹ is (C₁-C₆)alkyl substitutedwith 1 to 3 hydroxy. Alternatively, in another embodiment, R¹ is(C₁-C₆)alkyl substituted with 1 to 3 NH₂. Alternatively, in anotherembodiment, R¹ is (C₁-C₆)alkyl substituted with —C(═O)NH₂.Alternatively, in another embodiment, R¹ is a 3-7 membered heterocycle,wherein said heterocycle contains 1 to 3 heteroatoms independentlyselected from O, N, or S.

In one particular embodiment, the invention is:

or a pharmaceutically acceptable salt thereof.

In another particular embodiment, the invention is:

or a pharmaceutically acceptable salt thereof.

In another particular embodiment, the invention is:

or a pharmaceutically acceptable salt thereof.

In another particular embodiment, the invention is:

or a pharmaceutically acceptable salt thereof.

In another particular embodiment, the invention is:

or a pharmaceutically acceptable salt thereof.

In another embodiment, the compound of formula I has the formula (IB):

wherein R¹ is selected from the group consisting of:

and pharmaceutically acceptable salts thereof.

In one embodiment the invention is a compound of formula (IB) wherein R¹is selected from the group consisting of:

and pharmaceutically acceptable salts thereof.

In another embodiment the invention is a compound of formula (IB)wherein R¹ is selected from the group consisting of:

and pharmaceutically acceptable salts thereof.

In another embodiment the invention is a compound of formula (IB)wherein R¹ is selected from the group consisting of:

and pharmaceutically acceptable salts thereof.

In another embodiment the invention is a compound of formula (IB)wherein R¹ is selected from the group consisting of:

and pharmaceutically acceptable salts thereof.

In one embodiment, the pharmaceutically acceptable salt of compounds ofthe invention is a potassium or sodium salt.

In one embodiment, the pharmaceutically acceptable salt of compounds ofthe invention is a bis-potassium or bis-sodium salt.

In another embodiment, the invention is a pharmaceutical compositioncomprising the compounds described above, or pharmaceutically acceptablesalt thereof, and a pharmaceutically acceptable carrier.

In another embodiment, the invention is a method for the treatment of abacterial infection in a mammal comprising administering to said mammalan amount of a compound of formula (I) or pharmaceutically acceptablesalt thereof that is effective in treating a bacterial infection. In oneparticular embodiment the bacterial infection is resistant orsusceptible. In another particular embodiment, the bacterial infectionis MDR (multi-drug resistant). In one embodiment, the bacterialinfection is selected from the group consisting of respiratory tractinfections, lung infection in cystic fibrosis patients, complicatedurinary tract infections, burn infections, wound infections, bloodinfections, complicated skin and soft tissue infections, nailinfections, ear infections, infections caused from medical devices,infections caused from a catheter, noscomial pneumonia,ventilator-associated pneumonia (VAP), community-acquired pneumonia(CAP), bacteremia, hot-tub rash (dermatitis), and post-operativeinfection in radial keratotomy surgery in humans. In another embodiment,the bacterial infection is selected from the group consisting ofNosocomial pneumonia, ventilator-associated pneumonia (VAP), complicatedUTI (urinary tract infection), complicated skin and skin structure, andbacteremia. In another embodiment, the bacterial infection is a burninfection. In another embodiment, the bacterial infection is a lunginfection in cystic fibrosis patients.

The present invention also relates to a method of treating infectioncaused by Pseudomonas aeruginosa, Escherichia coli, a Klebsiellaspecies, or an Acinetobacter species, comprising administering atherapeutically effective amount of the compound of formula (I) orpharmaceutically acceptable salt thereof to a mammalian subject in needthereof. In one particular embodiment, the infection is caused byPseudomonas aeruginosa.

The present invention also relates to a method of treating infection byPseudomonas aeruginosa that is resistant to doripenem, meropenem orpiperacillin comprising administering a therapeutically effective amountof the compound of formula (I) or pharmaceutically acceptable saltthereof to a mammalian subject in need thereof.

The present invention also relates to a composition comprising acompound of formula (I), or pharmaceutically acceptable salt thereof,and an additional antibacterial agent selected from the group consistingof beta-lactams, aminoglycosides, polymyxins, penicillins, andlincosamides. In one embodiment, the additional antibacterial agent is abeta-lactam selected from the group consisting of cephalosporins,carbapenems, and beta-lactamase inhibitors or beta-lactam/beta-lactamaseinhibitor combinations. In another embodiment, the additionalantibacterial agent is selected from the group consisting ofclindamycin, metronidazole, imipenem, meropenem, doripenem, ertapenem,cefotetan, cefepime, and cefpirome, or a third generation cephalosporin.In one particular embodiment, the additional antibacterial agent iscefepime. In another embodiment, the addition antibacterial agent ismeropenem. In another embodiment of the composition, the compound is:

or a pharmaceutically acceptable salt thereof. In another embodiment ofthe composition, the compound is:

or pharmaceutically acceptable salt thereof. In another embodiment ofthe composition, the compound is:

or pharmaceutically acceptable salt thereof. In another embodiment ofthe composition, the compound is:

or pharmaceutically acceptable salt thereof. In another embodiment ofthe composition, the compound is:

or pharmaceutically acceptable salt thereof.

In another embodiment, the composition is one of the specific compoundsshown above and the additional anti-bacterial agent is cefepime.

In another embodiment, the composition is one of the specific compoundsshown above and the additional anti-bacterial agent is meropenem.

The present invention also relates to a complex or chelate comprising acompound of formula (I) or a pharmaceutically acceptable salt thereof,as a ligand and an iron (+3) cation, wherein the ratio of ligand to ironcation is from about 1:1 to about 3:1, respectively. In one embodiment,the ratio is about 3:1.

The present invention includes methods of treatment of the human ornon-human animal body, e.g., to combat or treat (including prevention)bacterial infections, comprising administering to subjects a useful oreffective amount of a compound of the invention, including aphysiologically acceptable salt or solvate thereof, and includingcompositions.

The compounds of the invention can also be combined with other activeingredients as desired to attain combination therapy for more than onecondition or biological target. For example, the compounds of theinvention can be combined with other anti-infectives, or agents thatincrease the efficacy or other properties of the anti-infective, e.g.,efflux inhibitors.

The compounds of formula (I) are useful for treating a patient sufferingfrom a disorder such as, e.g., a bacterial infection.

Bacterial infections amenable to treatment by compounds of formula (I),pharmaceutical compositions, and methods of the present inventioninclude those caused by Acinetobacter baumannii, Acinetobacter spp.,Bacteroides fragilis, Citrobacter diversus, Citrobacter freundii,Enterobacter aerogenes, Enterobacter cloacae, Escherichia coli,Haemophilus influenzae β-lactamase negative, Haemophilus influenzaeβ-lactamase positive, Klebsiella oxytoca, Klebsiella pneumoniae(including those encoding extended-spectrum β-lactamases (hereinafter“ESBLs”), Legionella pneumophila, Moraxella catarrhalisβ-lactamase-negative, Moraxella catarrhalis β-positive, Morganellamorganii, Neisseria meningitidis, Prevotella spp. (and members of theEnterobacteriaceae that express ESBLs and AmpC-type beta-lactamases thatconfer resistance to currently available cephalosporins, cephamycins andbeta-lactam/beta-lactamase inhibitor combinations), Proteus mirabilis,Pseudomonas aeruginosa, Salmonella/Shigella, and Serratia marcescens.

The compounds of formula (I) may, in one embodiment, be used to treat avariety of hospital and community acquired infections such asrespiratory tract infections (including lung infection in cysticfibrosis patients), complicated urinary tract infections, burninfections, wound infections, blood infections, complicated skin andsoft tissue infections, nail and ear infections, infections caused frommedical devices (e.g., catheter, etc.), noscomial pneumonia (includingventilator-associated pneumonia (VAP)), community-acquired pneumonia(CAP), bacteremia, “hot-tub rash” (dermatitis), and post-operativeinfection in radial keratotomy surgery in humans (hereinafter “theinfections”).

In one embodiment, the infection is selected from the group consistingof noscomial pneumonia, ventilator-associated pneumonia, complicatedurinary tract infections, complicated skin & skin structure infections,and bacteremia.

In one embodiment, the composition of the invention comprises atherapeutically effective amount of a compound of formula (I) of theinvention.

The invention also relates to compositions of the invention whichcomprise any combination of one or more compounds of formula (I) and atleast one additional ingredient (hereinafter “the compositions of theinvention”).

Non-limiting examples of the at least one additional ingredient includeimpurities (e.g., intermediates present in the unrefined compounds offormula (I)), active or pharmaceutical agents as discussed below (e.g.,another antibacterial agent), pharmaceutically acceptable excipients, orone or more solvents (e.g., a pharmaceutically acceptable carrier asdiscussed herein).

Compositions of the invention that are suitable for administration to apatient in need thereof (e.g., a human) are also referred to herein as“pharmaceutical compositions of the invention.”

Administration of the compounds of the present invention (hereinafterthe “active compound(s)”) can be effected by any method that enablesdelivery of the compounds to the site of action. These methods includeoral routes, intraduodenal routes, parenteral injection (includingintravenous, subcutaneous, intramuscular, intravascular or infusion),topical, and rectal administration. In one particular embodiment, themethod of administration is intravenous.

The pharmaceutical composition may, for example, be in a form suitablefor oral administration as a tablet, capsule, pill, powder, sustainedrelease formulation, solution, suspension, for parenteral injection as asterile solution, suspension or emulsion, for topical administration asan ointment or cream or for rectal administration as a suppository. Thepharmaceutical composition may be in unit dosage forms suitable forsingle administration of precise dosages. The pharmaceutical compositionwill include a conventional pharmaceutical carrier or excipient and acompound according to the invention as an active ingredient. Inaddition, it may include other medicinal or pharmaceutical agents,carriers, adjuvants, etc.

Exemplary parenteral administration forms include solutions orsuspensions of active compounds in sterile aqueous solutions, forexample, aqueous propylene glycol or dextrose solutions. Such dosageforms can be suitably buffered, if desired.

Suitable pharmaceutical carriers include inert diluents or fillers,water and various organic solvents. The pharmaceutical compositions may,if desired, contain additional ingredients such as flavorings, binders,excipients and the like. Thus for oral administration, tabletscontaining various excipients, such as citric acid may be employedtogether with various disintegrants such as starch, alginic acid andcertain complex silicates and with binding agents such as sucrose,gelatin and acacia. Additionally, lubricating agents such as magnesiumstearate, sodium lauryl sulfate and talc are often useful for tabletingpurposes. Solid compositions of a similar type may also be employed insoft and hard filled gelatin capsules. Preferred materials, therefore,include lactose or milk sugar and high molecular weight polyethyleneglycols. When aqueous suspensions or elixirs are desired for oraladministration the active compound therein may be combined with varioussweetening or flavoring agents, coloring matters or dyes and, ifdesired, emulsifying agents or suspending agents, together with diluentssuch as water, ethanol, propylene glycol, glycerin, or combinationsthereof.

Methods of preparing various pharmaceutical compositions with a specificamount of active compound are known, or will be apparent, to thoseskilled in this art. For examples, see Remington's PharmaceuticalSciences, Mack Publishing Company, Easter, Pa., 15th Edition (1975).

The minimum amount of the compounds of formula (I) to be administered isa therapeutically effective amount. The term “therapeutically effectiveamount” means the amount of compound which prevents the onset of,alleviates the symptoms of, stops the progression of, and/or eliminatesa bacterial infection in a mammal, e.g., a human.

Typically, an effective dosing schedule of the compounds of formula (I)of the invention for adults is about 50 mg to about 3000 mg of acompound of formula (I) in a single dose; in another embodiment, aneffective single dose is about 100 mg to about 2000 mg. In anotherembodiment, an effective single dose is about 800 mg to about 1000 mg.Typically the dosages are given 1 to 4 times per day. In one embodiment,the dosages are given 3 times per day. In some cases, it may benecessary to use dosages outside these limits.

The compounds of formula (I) of the invention may be administered incombination with one or more additional medicinal or pharmaceuticalagents (“the additional active agent”). Such use of the compounds offormula (I) in combination with an additional active agent may be forsimultaneous, separate or sequential use.

In one embodiment, the additional active agent is an antibacterialagent.

In one embodiment the antibacterial agent is a β-lactam. Non-limitingexamples of β-lactams include cephalosporins (e.g., cefepime,ceftazidime, cefpirome, cefditoren pivoxil (Spectracef®), cefoperazone,ceftazidime, cefdinir, cefotaxime, cefpodoxime, cephalothin, cefaclor orcefixime), cephamycins (e.g., cefotetan), carbapenems (e.g., imipenem,meropenem, ertapenem, doripenem), beta-lactamase inhibitors andbeta-lactam/beta-lactamase inhibitor combinations such as sulbactam,clavulanic acid, tazobactam and piperacillin in combination withtazobactam (Zosyn®), and sulopenum.

In another embodiment the antibacterial agent is may be selected fromaminoglycosides (e.g., amikacin, gentamicin, kanamycin, neomycin,netilmicin, paromomycin, rhodostreptomycin, streptomycin, tobramycin,apramycin, etc.), polymyxins (e.g., polymyxin B, colistin),fluoroquinolones (norfloxacin, ciprofloxacin, levofloxacin (Levaquin®),moxifloxacin (Avelox®), or enoxacin), penicillins (e.g., amoxicillin,ampicillin, etc.), and lincosamides (e.g., clindamycin, lincomycin,etc.).

In another embodiment the additional anti-bacterial agent is selectedfrom metronidazole, glycopeptides (e.g., vancomycin, dalbavancin,telavancin, oritivancin), oxazolidinones (e.g., linezolid), lipeopetides(e.g., daptomycin), and tetracyclines including gylcylcyclines (e.g.,tigecycline).

Other non-limiting examples of additional antibacterial agents can befound in Walsh and Wright, Chemical Reviews 105(2):391-394 (2005); andBush et al., Current Opinion in Microbiology 7:466-476 (2004).

In one embodiment, the additional antibacterial agent is used incombination with compounds or pharmaceutically acceptable salts of theinvention to lower the frequency of resistance. Examples includecefepime, cefpirome, imipenem, meropenem, ertapenem, doripenem,sulopenem, ceftazidime, piperacillin/tazobactam, ciprofloxacin,levofloxacin, moxifloxacin, polymyxin B, and tigecycline.

In another embodiment, the additional antibacterial agent may be astandard anti-anaerobe drug used in combination with compounds orpharmaceutically acceptable salts of the invention to treatintra-abdominal infections. Examples include clindamycin, metronidazole,imipenem, meropenem, doripenem, ertapenem, cefotetan, cefepime,cefpirome, and third generation cephalosporins.

In another embodiment, the additional antibacterial agent may be anacceptable anti-Gram positive agent used in combination with compoundsor pharmaceutically acceptable salts of the invention for empirictherapy to treat P. aeruginosa and all Enterobateriaceae. Examplesinclude vancomycin, linezolid, daptomycin, dalbavancin, telavancin, andoritivancin.

In one embodiment, the one or more additional active agents, when used,are administered prior to administration of a compound of formula (I).In another embodiment, the one or more additional active agents, whenused, are administered after administration of a compound of formula(I). In another embodiment, the one or more additional active agents,when used, are administered at about the same time as administration ofa compound of formula (I).

The additional active agent may be administered by any route useful toadminister said additional active agent.

In one embodiment, the one or more additional active agents are presentin the pharmaceutical composition of the invention. Accordingly, inanother embodiment, the invention relates to a method of treating apatient with a pharmaceutical composition of the invention furthercomprising one or more additional active agents.

It is to be understood that any section headings and subheadings hereinare for the convenience of the reader and are non-limiting. For example,the subject matter in the Summary of the Invention has no special statussolely as a result of its placement in that section.

Unless otherwise indicated, the language and terms used in this documentare to be given their broadest reasonable interpretation as understoodby the relevant skilled artisan. In addition, in descriptions and claimsin which the subject matter (e.g., substitution at a given molecularposition) is recited as being selected from a group of possibilities,the recitation is specifically intended to include any subset of therecited group. In the case of multiple variable positions orsubstituents, any combination of group or variable subsets is alsocontemplated.

Unless otherwise stated, the following abbreviations have the followingmeaning: “L” means “liter”, “mL” means “milliliter”, “mol” means“moles”, “mmol” means “millimoles”, “Ac” means “acetyl”, “Ph” means“phenyl”, “Bz” means “benzoyl”, “DCM” or “CH₂Cl₂” means“dichloromethane”, “DMSO” means “dimethylsulfoxide”, “MIC” means“minimum inhibitory concentration”, “MS” means “Mass Spectrometry” (allsamples herein were analyzed either by LCMS-electrospray (gradientelution using acetonitrile, water, formic acid mixtures) or probe APCImethods), “LCMS” means “liquid chromatography mass spectrometry”, “NMR”means “nuclear magnetic resonance spectroscopy” (All samples herein wererun at 400 MHz on Varian instruments, unless otherwise indicated), “THF”means “tetrahydrofuran”, “spp.” means “species” and “cfu” means“colony-forming unit”.

As used herein, the term “(C₁-C₆)alkyl” refers to linear or branchedhydrocarbons (e.g., methyl, ethyl, n-propyl, isopropyl) of 1 to 6 carbonatoms in length.

Unless otherwise indicated, the term “heterocycloalkyl”, as used herein,refer to non-aromatic cyclic groups containing one or more heteroatoms,preferably from one to four heteroatoms, each preferably selected fromoxygen, sulfur and nitrogen. The heterocycloalkyl groups of thisinvention can also include ring systems substituted with one or more oxomoieties. Examples of non-aromatic heterocycloalkyl groups areaziridinyl, azetidinyl, pyrrolidinyl, piperidinyl, azepinyl,piperazinyl, 1,2,3,6-tetrahydropyridinyl, oxiranyl, oxetanyl,tetrahydrofuranyl, tetrahydrothienyl, tetrahydropyranyl,tetrahydrothiopyranyl, morpholino, thiomorpholino, thioxanyl,pyrrolinyl, indolinyl, 2H-pyranyl, 4H-pyranyl, dioxanyl, 1,3-dioxolanyl,pyrazolinyl, dihydropyranyl, dihydrothienyl, dihydrofuranyl,pyrazolidinyl, imidazolinyl, imidazolidinyl, 3-azabicyclo[3.1.0]hexanyl,3-azabicyclo[4.1.0]heptanyl, quinolizinyl, quinuclidinyl,1,4-dioxaspiro[4.5]decyl, 1,4-dioxaspiro[4.4]nonyl,1,4-dioxaspiro[4.3]octyl, and 1,4-dioxaspiro[4.2]heptyl.

Unless otherwise indicated, the term “heteroaryl”, as used herein,refers to an aromatic ring containing one or more heteroatoms(preferably oxygen, sulfur and nitrogen), preferably from one to fourheteroatoms. Examples of 5 to 6 membered heteroaryls are pyridinyl,pyridazinyl, imidazolyl, pyrimidinyl, pyrazolyl, triazolyl, pyrazinyl,tetrazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxazolyl,isothiazolyl, pyrrolyl, triazinyl, purinyl, oxadiazolyl, thiadiazolyl,furazanyl.

The term “heterocycle” includes heteroaryl and heterocycloalkyl rings aswell as non-aromatic heterocyclic rings containing zero or more doublebonds.

Unless otherwise apparent or indicated, the compounds of the inventionand term “compound” in the claims embraces any pharmaceuticallyacceptable salts or solvates, and any amorphous or crystal forms, ortautomers, whether or not specifically recited in context. Similarly, arecitation is open to any material or composition containing the recitedcompound (e.g., a composition containing a salt of a racemic mixture ofcompounds, tautomers, epimers, stereoisomers, impure mixtures, etc.).

The compounds of formula (I) may exist in unsolvated and solvated forms.Thus, it will be understood that the compounds of the invention alsoinclude hydrate and solvate forms as discussed below.

The term “solvent” as it relates to the compositions of the inventionincludes organic solvents (e.g., methanol, ethanol, isopropanol, ethylacetate, methylene chloride, and tetrahydrofuran) and water. The one ormore solvents may be present in a non-stoichiometric amount, e.g., as atrace impurity, or in sufficient excess to dissolve the compound of theinvention. Alternatively, the one or more solvents may be present in astoichiometric amount, e.g., 0.5:1, 1:1, or 2:1 molar ratio, based onthe amount of compound of the invention.

The term “solvate” is used herein to describe a noncovalent or easilyreversible combination between solvent and solute, or dispersion meansand disperse phase. It will be understood that the solvate can be in theform of a solid, slurry (e.g., a suspension or dispersion), or solution.Non-limiting examples of solvents include ethanol, methanol, propanol,acetonitrile, dimethyl ether, diethyl ether, tetrahydrofuran, methylenechloride, and water. The term ‘hydrate’ is employed when said solvent iswater.

A currently accepted classification system for organic hydrates is onethat defines isolated site, or channel hydrates—see Polymorphism inPharmaceutical Solids by K. R. Morris (Ed. H. G. Brittain, MarcelDekker, 1995). Isolated site hydrates are ones in which the watermolecules are isolated from direct contact with each other byintervening organic molecules. In channel hydrates, the water moleculeslie in lattice channels where they are next to other water molecules.

When the solvent or water is tightly bound, the complex will have awell-defined stoichiometry independent of humidity. When, however, thesolvent or water is weakly bound, as in channel solvates and hygroscopiccompounds, the water/solvent content will be dependent on humidity anddrying conditions. In such cases, non-stoichiometry will be the norm.

Unless otherwise indicated, the term “pharmaceutically acceptablesalt(s)”, as used herein, unless otherwise indicated, includes salts ofacidic or basic groups which can be present in the compounds. Compoundsthat are basic in nature are capable of forming a wide variety of saltswith various inorganic and organic acids. The acids that can be used toprepare pharmaceutically acceptable acid addition salts of such basiccompounds are those that form non-toxic acid addition salts. Thecompounds can form, e.g., sulfates, phosphates, citrates, acetates,tosylates, succinates, besylates, mesylates, lactates, andhydrochlorides. Basic salts can be mono or dibasic. In one preferredembodiment, the salt is a fumarate.

Unless otherwise indicated, the terms “treat,” “treatment,” and“treating”, as used herein in the context of using the compounds of thepresent invention, unless otherwise indicated, means reversing,alleviating, inhibiting the progress of one or more symptoms of suchdisorder or condition.

As used herein the term “patient” refers to a mammal such as, e.g., ahuman, dog, cat, horse, pig, cow, and the like. In one embodiment, thepatient is a human.

Unless otherwise indicated, the term “pharmaceutical composition” refersto an active compound in any form suitable for effective administrationto a subject, e.g., a mixture of the compound and at least onepharmaceutically acceptable carrier.

Unless otherwise indicated, the term “pharmaceutically acceptablecarrier” refers to a material that can be administered to a subjecttogether with a compound in a pharmaceutical composition. The carriershould not destroy the pharmacological activity of the compound andshould be non-toxic when administered in doses sufficient to deliver atherapeutic amount of the compound.

The term “excipient” means an inert material that is combined with thecompounds of formula (I) to produce a pharmaceutical composition or oraldrug dosage form. The term “pharmaceutically acceptable excipient” meansthat the excipient must be compatible with other ingredients of thecomposition, and not deleterious to the recipient thereof. Thepharmaceutically acceptable excipients are chosen on the basis of theintended dosage form.

Compounds of the present invention have asymmetric centers and thereforecan exist in different enantiomeric and diastereomeric forms. Theinvention includes all optical isomers and stereoisomers, and mixturesthereof in all ratios, and to all pharmaceutical compositions andmethods of treatment that can employ or contain them. Although specificcompounds exemplified in this application can be depicted in aparticular stereochemical configuration, compounds having either theopposite stereochemistry at any chiral centers or mixtures thereof arealso envisioned. The foregoing can be present as mixtures or enriched inany component to any degree. Where stereochemistry at a position is notspecified, such is intended to encompass either configuration or amixture of any ratio.

Compounds of this invention include pharmaceutically acceptablederivatives or prodrugs thereof. A “pharmaceutically acceptablederivative or prodrug” means any pharmaceutically acceptable salt,ester, salt of an ester or other derivative of a compound that, uponadministration to a recipient, is capable of providing (directly orindirectly) a compound of this invention or a metabolite or residuethereof. Particularly favored derivatives and prodrugs of the inventionare those that increase the bioavailability of the compounds when suchcompounds are administered to a patient (e.g., by allowing an orallyadministered compound to be more effectively absorbed into the blood),enhance delivery of the parent compound to a given biologicalcompartment, increase solubility to allow administration by injection,alter metabolism or alter rate of excretion.

The compounds of formula (I) may exhibit polymorphism. Polymorphiccompounds of formula (I) may be prepared by crystallization of acompound of the present invention under various conditions. For example,there may be employed various solvents (including water) or differentsolvent mixtures for recrystallization; crystallization at differenttemperatures; various modes of cooling ranging from very fast to veryslow cooling during crystallization. Polymorphs may also be obtained byheating or melting a compound of the present invention followed bygradual or fast cooling. The presence of polymorphs may be determined bysolid probe NMR spectroscopy, IR spectroscopy, differential scanningcalorimetry, powder X-ray diffraction or other such techniques.

The present invention includes compounds wherein one or more hydrogen,carbon or other atoms are replaced by different isotopes thereof. Suchcompounds can be useful as research and diagnostic tools in metabolismpharmacokinetic studies and in binding assays. Theseisotopically-labeled compounds are identical to those compounds offormula (I), but for the fact that one or more atoms are replaced by anatom having an atomic mass or mass number different from the atomic massor mass number predominantly found in nature. Examples of isotopes thatcan be incorporated into compounds of the invention include isotopes ofhydrogen, carbon, nitrogen, oxygen, and sulfur, such as, but not limitedto, ²H, ³H, ¹³C, ¹⁴C, ¹⁵N, ¹⁸O, ¹⁷O, and ³⁵S, respectively. Thecompounds of formula (I) of the invention containing the aforementionedisotopes and/or other isotopes of these atoms are within the scope ofthis invention. Certain isotopically-labeled compounds of formula (I),for example those into which radioactive isotopes such as ³H and ¹⁴C areincorporated, are useful in drug and/or substrate tissue distributionassays. Tritiated, i.e., ³H, and carbon-14, i.e., ¹⁴C, isotopes areparticularly preferred for their ease of preparation and detectability.Further, substitution with isotopes such as deuterium, i.e., ²H, canafford certain therapeutic advantages resulting from greater metabolicstability, for example increased in vivo half-life or reduced dosagerequirements and, hence, may be preferred in some circumstances.Isotopically-labeled compounds of the invention can generally beprepared by carrying out the procedures disclosed in the Schemes and/orin the Examples and described below, by substituting a readily availableisotopically-labeled reagent for a non-isotopically-labeled reagent.

The term “protecting group” refers to a suitable chemical group that canbe attached to a functional group and removed at a later stage to revealthe intact functional group. Examples of suitable protecting groups forvarious functional groups are described in T. W. Greene and P. G. M.Wuts, Protective Groups in Organic Synthesis, 2nd Ed., John Wiley andSons (1991 and later editions); L. Fieser and M. Fieser, Fieser andFieser's Reagents for Organic Synthesis, John Wiley and Sons (1994); andL. Paquette, ed. Encyclopedia of Reagents for Organic Synthesis, JohnWiley and Sons (1995). The term “hydroxy protecting group”, as usedherein, unless otherwise indicated, includes Ac, Bz, and various hydroxyprotecting groups familiar to those skilled in the art, including thegroups referred to in Greene.

The examples and preparations provided below further illustrate andexemplify the compounds of the present invention and methods ofpreparing such compounds. It is to be understood that the scope of thepresent invention is not limited in any way by the scope of thefollowing examples and preparations.

All patents, patent applications, publications, test methods,literature, and other materials cited above and below herein are herebyincorporated herein by reference in their entireties.

DETAILED DESCRIPTION OF THE INVENTION

As noted above, in one embodiment, the present invention relates tocompounds of formula (I) and pharmaceutically acceptable salts thereof,as described above. The compounds of formula (I) are depictedstructurally in the Summary of the Invention an elsewhere herein for theconvenience of the reader.

General Preparation Methods

The compounds of the present invention may be prepared according to thedescriptions, schemes, and examples herein, which are non-limiting, incombination with the knowledge of the skilled artisan.

The compounds of the present invention can be prepared as outlined inschemes A through C. Compounds of the general formula I (Scheme A),prepared as described in Yamawaki, K., et al., Bioorganic & MedicinalChem., (2007), 15, 6716 and Yamamoto, H., et al., Bioorganic andMedicinal Chem., (2002), 10, 1535, can be reacted with hydroxylamines ofthe general formula II (prepared as described in WO 2007/065288,published Jun. 14, 2007) in a solvent such as methanol at ambienttemperature for approximately 2 hours to form carboxylic acids of theformula III. Activated esters of the formula IV can be prepared byreaction of compounds of the formula III with N-hydroxysuccinamide inthe presence of coupling reagent such as dicyclohexylcarbodiimide ordiisopropylcarbodiimide in a solvent such as dichloromethane at ambienttemperature. A compound of formula V, prepared as described by Waulte,S. R. et al. J. Org. Chem (1986), 51, 3133; Paloma, C., et al., J. Org.Chem. (1997), 62, 2070; Lall, M. S., et al., J. Org. Chem. (2002), 67,1536 and Chhabra, S. R., et al., J. Org. Chem. (2002), 67, 4017, can begenerated by deprotection of the corresponding N-benzyloxycarbonyl (Cbz)protected compound by hydrogenolysis at ambient temperature in thepresence of palladium on carbon, under approximately two to fouratmospheres of hydrogen gas, in a solvent such as methanol, ethanol,tetrahydrofuran, toluene or acetic acid sometimes requiring a binarycombination thereof. If the hydrogenation is done in the presence ofacetic acid, the intermediate aminoazetidinone can be isolated as theacetate salt and subsequently reacted with compounds of the formula IVin solvents such as methanol, ethanol or acetonitrile in the presence ofa base such as triethylamine to form amides of the general formula VI.When acetic acid is not used in the hydrogenation, the aminoazetidinonesproduced, once the catalyst is removed by filtration, can be reacted insitu with compounds of the formula IV to generate amides of the formulaVI.

Triazolones of the formula XI can be prepared as outlined in Scheme B.Starting from commercially available Kojic acid (CAS number: 501-30-4),compound VII can be prepared in five steps as described in EP 0281289,published Feb. 19, 1988. Reaction of VII with phosgene or a phosgeneequivalent such as carbonyldiimidazole in a solvent such asdichloromethane or tetrahydrofuran at ambient temperature producescompound VIII. Reaction of compound VIII with a primary amine of formulaIX in a solvent such as tetrahydrofuran at elevated temperature such asbetween 40° C. and 60° C. will produce compounds of the general formulaX. Compounds of the formula X can be cyclized to form compounds of theformula XI by reaction in water at reflux in the presence of a base suchas sodium hydroxide or potassium hydroxide. Alternatively, in somecases, a similar cyclization reaction can be accomplished by reaction ofcompounds of the formula X inN-trimethylsilyl-N-methyltrifluoroacetamide (MSTFA) at approximately150° C. resulting from microwave irradiation.

The coupling of compounds VI and XI and the final construction of thecompounds of the present invention can be accomplished as outlined inScheme C. The coupling of VI and XI to generate compounds of the generalformula XII can be accomplished by first reacting compounds of theformula XI with excess MSTFA in tetrahydrofuran at approximately 40° C.for one to two hours followed by removal of the tetrahydrofuran, excessMSTFA and byproducts under vacuum. Separately, compounds of the formulaVI can be reacted with chlorosulfonylisocyanate (CSI) in dichloromethaneat 0° C. for approximately 45 minutes. The adduct of the compound offormula XI can then be re-dissolved in tetrahydrofuran and to thismixture added the adduct from reaction of the compound of formula VIwith CSI. Stirring of these two components at 0° C. for approximatelytwo hours followed by stirring at ambient temperature for up to 18 hoursproduces the compounds of the general formula XII. Alternatively, thiscoupling reaction can be accomplished as follows: the CSI adductprepared as described above is mixed with the compound of formula XI,which can be silylated by reaction with excess hexamethyldisilizide(HMDS) in the presence of a catalytic amount of trimethylsilylchliride(TMS-Cl) at approximately 140° C. After cooling to ambient temperature,this material can be dissolved in a solvent such as dichloromethane andmixed the CSI adduct generating the compound of formula XII. Removal ofthe benzyl protecting groups from compounds of the formula XII can beaccomplished by reaction with between two and four atmospheres ofhydrogen gas in a binary solvent system consisting of tetrahydrofuranand acetic acid at ambient temperature and in the presence of apalladium catalyst such as palladium black. Following removal of thecatalyst and solvent, treatment of the crude material with an acid suchas trifluoroacetic acid in a solvent such as dichloromethane at ambienttemperature removes the tertiary-butyloxycarbonyl protecting group andthe tertiary-butylester if contained within R⁶. The crude material ofthe present invention (XIII) can then be purified by reverse-phasechromatography using a C18 resin with a gradient mobile phase consistingof acetonitrile and water, buffered with formic acid. The sodium saltswith the general formula XIV can then be generated from the compounds offormula XIII by treatment with sodium bicarbonate in water followed bylyophilization. If a second acidic site is present within R⁶ such as acarboxylic acid, the bis-sodium salts of the formula XIV can be producedfollowing the same procedure, but adding a second equivalent of sodiumbicarbonate prior to lyophilization.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding description, practice the present invention toits fullest extent. The following detailed examples describe how toprepare the various compounds and/or perform the various processes ofthe invention and are to be construed as merely illustrative, and notlimitations of the preceding disclosure in any way whatsoever. Thoseskilled in the art will promptly recognize appropriate variations fromthe procedures both as to reactants and as to reaction conditions andtechniques.

EXAMPLES

The Examples below were generally carried out under inert atmosphere(nitrogen or argon), particularly in cases where oxygen ormoisture-sensitive reagents or intermediates were employed. Commercialsolvents and reagents were generally used without further purification.All products were dried before characterization or use in subsequentchemistry. Chemical shifts for nuclear magnetic resonance (NMR) data areexpressed in parts per million (ppm, δ) referenced to residual peaksfrom the deuterated solvents employed.

Example 1 Preparation of2-({[(1E)-1-(2-amino-1,3-thiazol-4-yl)-2-{[(3S)-1-({[4-ethyl-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2-oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid (1)

Compound 1 was prepared by the procedures depicted in schemes 1 to 6 andoutlined in detail below.

Step 1. Preparation of benzyl 4,5-bis(benzyloxy)pyridine-2-carboxylate(C4)

A. Preparation of 5-(benzyloxy)-2-(hydroxymethyl)-4H-pyran-4-one (C1).5-Hydroxy-2-(hydroxymethyl)-4H-pyran-4-one (300 g, 2.11 mol) wasdissolved in methanol (9 L) and treated with potassium carbonate (439 g,3.18 mol), followed by slow addition of benzyl chloride (433 g, 3.42mol). The reaction mixture was stirred at 65° C. for 8 hours. Aftercooling to room temperature, it was stirred for an additional 16 hours,then concentrated in vacuo to a thick paste. This residue was cooled to10° C. and diluted with ice water, resulting in a precipitate that wasgathered by filtration to provide C1 as a solid. Yield: 325 g, 1.40 mol,66%. ¹H NMR (400 MHz, DMSO-d₆) δ 4.29 (s, 2H), 4.94 (s, 2H), 6.32 (s,1H), 7.33-7.42 (m, 5H), 8.17 (s, 1H).

B. Preparation of 5-(benzyloxy)-4-oxo-4H-pyran-2-carboxylic acid (C2). Asolution of chromium(VI) oxide (64.6 g, 0.646 mol) in water (90 mL) wascooled to −5° C. and treated drop-wise with concentrated sulfuric acid(56 mL). This was diluted with additional water (40 mL), and then addeddrop-wise to a cold (−5° C.) solution of C1 (100 g, 0.43 mol) in acetone(4.5 L). The reaction mixture was stirred at 20° C. for 3 hours, thenfiltered through a pad of Celite®. Concentration of the filtrateprovided a residue, which was washed with hexane to provide C2. Yield:80 g, 0.325 mol, 76%. ¹H NMR (400 MHz, DMSO-d₆) δ 4.97 (s, 2H), 6.93 (s,1H), 7.34-7.42 (m, 5H), 8.37 (s, 1H).

C. Preparation of 5-(benzyloxy)-4-oxo-1,4-dihydropyridine-2-carboxylicacid (C3). A mixture of C2 (100 g, 0.406 mol) and aqueous ammoniumhydroxide solution (25%, 1 L) was stirred in an autoclave for 1 hour,and then heated at 83° C. for 7 hours at atmospheric pressure. Aftercooling slowly over about 18 hours, the reaction mixture was acidifiedto pH 3 with concentrated hydrochloric acid. The resulting precipitatewas collected by filtration, washed with water, and dissolved insaturated aqueous sodium bicarbonate solution. The solution was washedwith dichloromethane, then acidified with concentrated hydrochlorideacid. The resulting solid was collected by filtration, washed with waterand dried at 50° C. to provide C3. Yield: 85 g, 0.347 mol, 85%. ¹H NMR(400 MHz, DMSO-d₆) δ 5.17 (s, 2H), 7.17 (br s, 1H), 7.33-7.49 (m, 7H).

D. Preparation of C4. Benzyl chloride (105.6 mL, 0.918 mol) was added toa solution of C3 (90 g, 0.367 mol) in dimethylformamide (1.25 L).Potassium carbonate (124.8 g, 0.903 mol) was added, and the mixture wasstirred at 80° C. for 16 hours. After cooling to room temperature, thereaction was treated with ice water, and the resulting solid wascollected by filtration and purified by silica gel chromatography toafford C4. Yield: 50 g, 0.118 mol, 32%. MS m/z 426 (M+1). ¹H NMR (400MHz, DMSO-d₆) δ 5.32 (s, 6H), 7.33-7.46 (m, 15H), 7.76 (s, 1H), 8.37 (s,1H).

Step 2. Preparation of5-(4,5-bis(benzyloxy)pyridin-2-yl)-1,3,4-oxadiazol-2(3H)-one (C6)

A. Preparation of 4,5-bis(benzyloxy)pyridine-2-carbohydrazide (C5).Hydrazine monohydrate (47.5 mL, 978 mmol) was added drop-wise over 10minutes to a suspension of C4 (20 g, 47.0 mmol) in methanol (100 mL).The resulting mixture was heated to 65° C. for 2 hours, then cooled toroom temperature and filtered under vacuum. The collected solids werewashed with methanol to provide C5 as a white solid. Yield: 15.4 g, 44.1mmol, 94%. LCMS m/z 350.1 (M+1). ¹H NMR (400 MHz, DMSO-d₆) δ 4.47 (d,J=4.6 Hz, 2H), 5.30 (s, 2H), 5.32 (s, 2H), 7.31-7.48 (m, 10H), 7.67 (s,1H), 8.23 (s, 1H), 9.65 (t, J=4.5 Hz, 1H).

B. Preparation of5-[4,5-bis(benzyloxy)pyridin-2-yl]-1,3,4-oxadiazol-2(3H)-one (C6).Carbonyl diimidazole (97%, 2.87 g, 17.2 mmol) was added to a suspensionof C5 (5.00 g, 14.3 mmol) in tetrahydrofuran (75 mL). The reactionmixture was stirred at room temperature for 3 hours, during which timethe white suspension became a homogeneous solution, and then a whitesuspension. The solid was collected by filtration and washed withtetrahydrofuran (3×5 mL) to provide C6 as a white solid. Yield: 4.92 g,13.1 mmol, 92%. LCMS m/z 376.1 (M+1). ¹H NMR (400 MHz, DMSO-d₆) δ 5.31(s, 2H), 5.33 (s, 2H), 7.32-7.48 (m, 10H), 7.56 (s, 1H), 8.38 (s, 1H),12.64 (br s, 1H).

Step 3. Preparation of5-(4,5-bis(benzyloxy)pyridin-2-yl)-4-ethyl-2H-1,2,4-triazol-3(4H)-one(C8)

A. Preparation of 1-(3,4-bis(benzyloxy)picolinoyl)-4-ethylsemicarbazide(C7). To a solution of C5 (0.75 g/0.215 mol) in 5 mLN,N-dimethylformamide at 5° C. was added slowly a solution of 229 mg(3.22 mmol) of ethylisocyanate in 5 mL of tetrahydrofuran and theresulting mixture stirred at room temperature for 2 hours, at whichpoint, the reaction mixture was transferred to a solution containing0.161 g (0.0032 mol) hydrazine monohydrate in 10 mL of tetrahydrofuranat a rate such to maintain a temperature less than 15° C. Once added,the resulting mixture stirred at room temperature for 1 hour, at whichpoint the mixture was poured into 50 mL of ice-water forming aprecipitate, which was collected by filtration and dried in vacuoaffording C7 as a white solid. LCMS m/z 421 (M+1). ¹H NMR (400 MHz,CDCL3-d₆) δ 1.25 (t, J=6.2 Hz, 3H), 4.25 (br. d, 2H), 5.24 (br. s, 4H),7.31-7.46 (m, 10H), 7.55 (br. s, 1H), 8.18 (s, 1H).

B. Preparation of5-(4,5-bis(benzyloxy)pyridin-2-yl)-4-ethyl-2H-1,2,4-triazol-3(4H)-one(C8) (Cyclization Method 1). To a stirred solution of 0.42 g (0.999mmol) of C7 was added 8 equivalents (0.448 g/7.99 mmol) of potassiumhydroxide dissolved in 2 mL of water and the resulting mixture heated toreflux for 24 hours at which point the reaction mixture was concentratedto dryness in vacuo. The crude product was then purified by columnchromatography (silica-gel, 3 to 5% methanol in ethylacetate producing0.683 g (46%) of compound C8. LCMS m/z 403.3 (M+1). ¹H NMR (400 MHz,CDCL3-d₆) δ 1.26 (t, J=7.3 Hz, 3H), 4.26 (q, J=6.6 Hz, 2H), 5.24 (s,4H), 7.29-7.47 (m, 10H), 7.57 (s, 1H), 8.16 (s, 1H), 9.86 (br. s, 1H).

Step 4. Preparation of (3S)-3-aminoazetidin-2-one (C10)

Benzyl[(3S)-2-oxoazetidin-3-yl]carbamate (C9, 13.37 g, 60.7 mmol) wasmixed with degassed ethanol (500 mL) and toluene (125 mL). For synthesisof C9, see M. J. Miller et al., Tetrahedron, 1983, 39, 2571-2575, and M.S. Lall et al., Journal of Organic Chemistry 2002, 67, 1536-1547. Thereaction mixture was sonicated until all the solids dissolved, thenpurged with nitrogen. Palladium on carbon (10%, 4.45 g) was added, andthe reaction mixture was hydrogenated on a Parr shaker for 1 hour at 15psi. The palladium was removed by filtration through Celite® undernitrogen, and rinsed with degassed ethanol. The filtrate, containingC10, was carried directly into the coupling reaction with C12, Step 4B.Yield: assumed quantitative. Material from a similar experiment wasconcentrated to dryness to obtain NMR data: ¹H NMR (400 MHz, DMSO-d₆) δ2.12 (br s, 2H), 2.78 (dd, J=5.1, 2.3 Hz, 1H), 3.31 (dd, J=5.3, 5.3 Hz,1H), 3.97 (m, 1H), 7.69 (br s, 1H).

Step 5. Preparation of tert-butyl2-({[(1Z)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-oxo-2-{[(3S)-2-oxoazetidin-3-yl]amino}ethylidene]amino}oxy)-2-methylpropanoate(C13)

A. Preparation of tert-butyl2-[({(1Z)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-[(2,5-dioxopyrrolidin-1-yl)oxy]-2-oxoethylidene}amino)oxy]-2-methylpropanoate(C12). 1-Hydroxypyrrolidine-2,5-dione (N-hydroxysuccinimide, 8.84 g,76.8 mmol) was added to a suspension of(2Z)-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}[(2-tert-butoxy-1,1-dimethyl-2-oxoethoxy)imino]aceticacid (C11, 30 g, 70 mmol) in dichloromethane (400 mL). For synthesis ofC11, see K. Yamawaki et al., Bioorganic and Medicinal Chemistry 2007,15, 6716-6732. The mixture was cooled to 0° C.,N,N′-dicyclohexylcarbodiimide (97%, 15.6 g, 73.3 mmol) was added, andthe reaction was stirred at 0° C. for 30 minutes and then at roomtemperature for 3 hours. The mixture was filtered through Celite® andconcentrated in vacuo to afford C12 as a white solid. Yield: 36.17 g,68.7 mmol, 98%. LCMS m/z 527.2 (M+1). ¹H NMR (400 MHz, CDCl₃) δ 1.43 (s,9H), 1.54 (s, 9H), 1.61 (s, 6H), 2.91 (br s, 4H), 7.50 (s, 1H), 8.31 (brs, 1H).

B. Preparation of C13. A solution of C10 (5.23 g, 60.7 mmol) inethanol/toluene (900 mL, solution obtained in Step 4) was treated withcompound C12 (26.6 g, 50.6 mmol), and the reaction mixture was slowlyconcentrated under reduced pressure, over the course of an hour, toone-third of its original volume. The resulting suspension was stirredat 35° C. under nitrogen for about 18 hours. Removal of solvent in vacuoafforded a crude product, which was dried under vacuum for 30 minutes.The resulting solids were partitioned between 1:1 ethylacetate/tetrahydrofuran (1 L) and aqueous sodium bicarbonate solution(500 mL). Additional water was required to dissolve solids observedduring the separation. The aqueous layer was extracted with 1:1 ethylacetate/tetrahydrofuran (2×300 mL), and the combined organic layers werefiltered and concentrated in vacuo. The crude solid was triturated with3:2 ethyl acetate/heptane (60 mL) for 30 minutes, and the solids werecollected by filtration, rinsing with heptane, to provide C13 as a whitesolid. Yield: 22.08 g, 44.4 mmol, 88%. LCMS m/z 498.6 (M+1). ¹H NMR (400MHz, CD₃OD) δ 1.47 (s, 9H), 1.52 (s, 6H), 1.54 (s, 9H), 3.39 (dd, J=5.7,2.5 Hz, 1H), 3.65 (dd, J=5.5, 5.5 Hz, 1H), 5.10 (dd, J=5.3, 2.5 Hz, 1H),7.34 (s, 1H).

Step 6. Preparation of Preparation of2-({[(1E)-1-(2-amino-1,3-thiazol-4-yl)-2-{[(3S)-1-({[4-ethyl-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2-oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid (1)

A. Preparation of C14 (Coupling Method 1). To a stirred solution of C8(180 mg/0.45 mmol) in 3 mL of tetrahydrofuran was added 6.0 equivalentsof N-trimethylsilyl-N-methyltrifluoroacetamide (MSTFA, Aldrich ampoule)forming a pale yellow solution, which stirred at room temperature for 45minutes. The mixture was then concentrated under reduced pressure andheated under vacuum (high vac) at 45° C. for 1 hour. Separately, to0.223 g (0.45 mmol) of C13 dissolved in 4 mL dichloromethane and cooledto 0° C. was added 0.082 g (0.58 mmol/0.051 mL) ofchlorosulfonylisocyanate and the resulting solution stirred at 0° C. for30 minutes. At this point, tetrahydrofuran (3 mL) was added to theadduct of C8 and the resulting solution introduced to the CSI reactionvia cannula. The resulting solution stirred at 0° C. for 1 hour thenbrought to room temperature and concentrated under reduced pressure. Thecrude material was cleaned up by column chromatography (silica-gel, 45to 60% ethylacetated in heptane) affording 332 mg of C14 in a mixturethat was carried forward without additional purification. LCMS m/z1003.2 (M-1).

B. Preparation of compound 1. In a Parr bottle was placed 0.190 g (0.19mmol) of C14 dissolved in 20 mL of methanol and the solution degassedwith nitrogen gas. Palladium-black (0.063 g) was then added and mixtureagitated under an atmosphere of 13 psi hydrogen at room temperature for40 min (reaction complete by LCMS). The reaction mixture was thenfiltered through Celite® and concentrated to dryness in vacuo. Thematerial was then carried on crude by dissolving in 10 mL ofdichloromethane. To this solution was then added 10 mL oftrifluoroacetic acid and the resulting mixture stirred at roomtemperature for 2 hours, at which time the reaction mixture wasconcentrated in vacuo. The crude product (1) was then purified bypreparative HPLC (Symmetry C8, 3 to 23% acetonitrile in water with 0.1%formic acid modifier). Approximately 5 mg of 1 were collected followingconcentration to dryness in vacuo. LCMS m/z 669.4 (M+1). ¹H NMR (400MHz, CD₃OD) δ 1.0-1.2 (m, 6H), 1.3-1.5 (br. s, 5H), 3.97 (d, J=6.8 Hz,2H), 4.88 (br. s, 1H), 6.81 (s, 1H), 7.32 (s, 1H), 7.99 (s, 1H), 9.05(d, J=4.2 Hz, 1H).

Example 2 Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({4-[2-(dimethylamino)ethyl]-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid (2)

Compound 2 was prepared by the procedures depicted in scheme 7 andoutlined in detail below.

Step 1. Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({4-[2-(dimethylamino)ethyl]-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid (2) and diasteriomeric diol mixture (Example 10)

A. Preparation of C16. Compound C15 was prepared in an analogous mannerto C14 in example 1 using coupling method 1. LCMS m/z 991.8 (M+1). ¹HNMR (400 MHz, DMSO-d₆) δ 1.33-1.39 (m, 9H), 1.41-1.45 (br. s, 6H),3.32-3.38 (m, 1H), 6.67 (t, J=8.2 Hz, 1H), 4.67 (m, 1H), 4.85-4.92 (m,1H), 4.98 (d, J=5.8 Hz, 1H), 5.26 (d, J=9.3 Hz, 2H), 5.73-5.86 (m, 1H),7.27-7.49 (m, 10H), 7.58 (s, 1H), 8.31 (s, 1H), 8.99 (d, J=9.34 Hz, 1H).To a stirred solution of C15 (0.30 g/0.3 mmol) in 5 mL of 9:1acetone/water was added 0.138 g (1.18 mmol) N-methylmorpholine-N-oxide(NMO) followed by 0.746 g (0.09 mmol) of osmium tetroxide and theresulting mixture stirred 16 hours at room temperature. Another additionof NMO and osmium tetroxide were then added and mixture stirred anadditional 24 hours, at which time the reaction was complete by LCMS.The reaction was filtered through Celite®, concentrated in vacuo thenpurified by column chromatography (silica; 30 to 100% ethylacetate inheptane then switched to 3 to 7% methanol in dichloromethane collecting0.302 g of C16. LCMS m/z 1051.3 (M+1). ¹H NMR (400 MHz, DMSO-d₆) δ1.33-1.38 (m, 9H), 1.42 (s, 6H), 3.20-3.26 (m, 2H), 3.31-3.37 (m, 1H),3.58-3.69 (m, 2H), 3.94-4.11 (m, 2H), 4.49-4.58 (m, 1H), 4.89 (br. s,1H), 4.94 (dd, J=5.4 Hz, J=10.1 Hz, 1H), 5.24-5.29 (m, 4H), 7.27-7.48(m, 10H), 7.52 (s, 1H), 8.31 (s, 1H), 8.98 (d, J=8.7 Hz, 1H). Thismaterial was then deprotected in an analogous manner to that describedfor C14 for preparing compound I in example 1 in order to prepareexample 10.

B. Preparation of C17. In a flame dry flask was placed C15 (0.486 g,0.48 mmol) dissolved in 8 mL of 3:1 dioxane/water and to this mixturewas then added sodium periodate (0.311 g, 1.43 mmol) and osmiumtetroxide (0.025 g, 0.003 mmol) and the resulting mixture stirred for 16hours at room temperature (reaction complete by LCMS). The reactionmixture was then partitioned between saturated sodium bicarbonate andethylacetate. The organic layer was washed with saturated brine, driedover sodium sulfate, filtered and concentrated to dryness in vacuo. Thecrude product was then purified by column chromatography (silica-gel, 30to 100% ethylacetate in heptane then switched to 3 to 7% methanol indichloromethane collecting 0.230 g of C17, which appears by ¹H NMR toexist as a hydrate. LCMS m/z 1019.9 (M+1). ¹H NMR (400 MHz, CD₃OD) δ1.38-1.56 (m, 24H), 3.72 (t, J=4.7 Hz, 1H), 3.84 (t, J=4.1 Hz, 1H),3.89-3.56 (m, 1H), 4.16-4.22 (m, 2H), 4.45 (t, J=5.3 Hz, 1H), 4.72-4.78(m, 1H), 5.00-5.09 (m, 1H), 5.19-5.29 (m, 4H), 7.19-7.49 (m, 10H), 7.77(s, 1H), 8.11 (s, 1H), 8.22 (d, J=9.4 Hz, 1H).

C. Preparation of C18 and compound 2. To a stirred solution of C17 (1.22g, 1.20 mmol) in 10 mL tetrahydrofuran was added dimethylamine (0.098 g,1.2 mmol) and 3 equivalents of glacial acetic acid (0.215 mL, 3.59 mmol)and the resulting solution stirred at room temperature for 2 hours.Sodium triacetoxyborohydride (0.532 g, 2.51 mmol) was then added and theresulting mixture stirred at room temperature for 18 hours. The reactionmixture was partitioned between saturated sodium bicarbonate andethylacetate, the organic layer washed with saturated brine, dried oversodium sulfate, filtered and concentrated to dryness in vacuo. The crudeproduct was purified by column chromatography (silica-gel, 30 to 100%ethylacetate in heptane then switched to 5 to 10% methanol indichloromethane) collecting 0.340 g of C18. LCMS m/z 1048.9 (M+1). ¹HNMR (400 MHz, CD₃OD) δ 1.38-1.54 (m, 24H), 2.44 (s, 1H), 2.85 (s, 6H),3.40 (br. s, 1H), 3.71-3.77 (m, 1H), 3.90 (t, J=6.0 Hz, 1H), 4.46 (br.s, 2H), 5.03 (s, 2H), 5.18-5.26 (m, 4H), 7.20-7.35 (m, 9H), 7.40 (d,J=7.0 Hz, 2H), 7.65 (s, 1H), 8.21 (s, 1H). Compound 2 was then preparedfrom C18 by deprotection and HPLC purification in an analogous manner tothat described for compound 1 of Example 1. LCMS m/z 712.5 (M+1). ¹H NMR(400 MHz, DMSO-d₆) δ 1.39 (s, 6H), 2.50 (s, 6H), 3.30-3.45 (m, assumed3H, obscured by water peak), 3.68 (m, 1H), 4.37 (m, 2H), 6.70 (s, 1H),7.31 (br s, 2H), 7.42 (s, 1H), 8.03 (s, 1H), 8.98 (d, J=7.0 Hz, 1H),9.99 (br s, 1H), 10.88 (br s, 1H).

Example 3 Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({4-[(2R)-2,3-dihydroxypropyl]-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidenelamino}oxy)-2-methylpropanoicacid, disodium salt (3)

Compound 3 was prepared by the procedures depicted in Schemes 8 to 10and described in detail below.

Step 1. Preparation of5-[4,5-bis(benzyloxy)pyridin-2-yl]-4-[(2R)-2,3-dihydroxypropyl]-2,4-dihydro-3H-1,2,4-triazol-3-one(C20)

A. Preparation of2-{[4,5-bis(benzyloxy)pyridin-2-yl]carbonyl}-N-[(2R)-2,3-dihydroxypropyl]hydrazinecarboxamide(C19). (2R)-3-Aminopropane-1,2-diol (0.291 g, 3.19 mmol) was added to asuspension of C6 (1.0 g, 2.66 mmol) in tetrahydrofuran (50 mL), and themixture was heated to 60° C. for 20 hours. After cooling to roomtemperature, the suspension was filtered, and the solid was washed withtetrahydrofuran (3×5 mL) to afford C19 as a white solid. Yield: 1.07 g,2.29 mmol, 86%. LCMS m/z 467.2 (M+1). ¹H NMR (400 MHz, DMSO-d₆) δ 2.93(m, 1H), 3.19 (m, 1H), 3.27 (m, 2H), 3.44 (m, 1H), 4.53 (t, J=5.8 Hz,1H), 4.77 (d, J=4.8 Hz, 1H), 5.33 (s, 4H), 6.31 (t, J=5.5 Hz, 1H),7.31-7.48 (m, 10H), 7.69 (s, 1H), 8.01 (br s, 1H), 8.28 (s, 1H), 10.04(br s, 1H).

B. Preparation of C20. A solution of C19 (3.00 g, 6.43 mmol) in aqueouspotassium hydroxide (1.6 M, 40.2 mL, 64.3 mmol) was heated at 100° C.for 13 hours, after which it was cooled to 0° C., diluted with water(100 mL) and acidified to pH 7 with concentrated hydrochloric acid. Theresulting solid was filtered and washed with water (3×10 mL) to affordC20, contaminated with about 30% of the hydrolysis product4,5-bis(benzyloxy)pyridine-2-carboxylic acid. Yield: 2.66 g, <5.93 mmol,<92%. LCMS m/z 449.2 (M+1) and 336.1 (M+1 for the hydrolysis product).¹H NMR (400 MHz, DMSO-d₆) δ 3.28 (m, 2H), 3.70 (m, 1H), 4.05 (dd, halfof ABX pattern, J=13.7, 5.0 Hz, 1H), 4.12 (dd, half of ABX pattern,J=13.7, 8.0 Hz, 1H), 4.61 (v br s, 1H), 5.01 (br s, 1H), 5.28 (s, 2H),5.31 (s, 2H), 7.32-7.48 (m, 10H), 7.58 (s, 1H), 8.32 (s, 1H), 12.03 (brs, 1H). Selected peaks for hydrolysis product: 5.29 (s), 7.70 (s), 8.28(s).

Step 2. Preparation of tert-butyl2-({[(1Z)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-({(3S)-1-[({4-[(2R)-2,3-dihydroxypropyl]-3-(5-hydroxy-4-oxo-1,4-di hydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoate(C22)

A. Preparation of tert-butyl2-({[(1Z)-2-({(3S)-1-[({3-[4,5-bis(benzyloxy)pyridin-2-yl]-4-[(2R)-2,3-dihydroxypropyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-oxoethylidene]amino}oxy)-2-methylpropanoate(C21). A mixture of C20 (4.00 g, 8.92 mmol) in tetrahydrofuran (35 mL)was treated with 2,2,2-trifluoro-N-methyl-N-(trimethylsilyl)acetamide(MSTFA, 98%, 10.2 mL, 53.7 mmol). After 45 minutes of stirring, thelight yellow milky mixture was concentrated in vacuo at 60° C. for 1hour, then dried under vacuum at 60° C. for 1.5 hours. In a separateflask, a suspension of C13 (4.88 g, 9.81 mmol) in dichloromethane (32mL) was cooled to 0° C., treated drop-wise with isocyanatosulfurylchloride (chlorosulfonyl isocyanate, 95%, 0.929 mL, 10.7 mmol) andallowed to stir for 30 minutes under ice-cooling. The material derivedfrom C20 was dissolved in tetrahydrofuran (8 mL), cooled to 0° C. Theice-cooled C13-containing reaction mixture was then transferred intothis solution via cannula. After stirring at 0° C. for 1 hour, then atroom temperature for 1.5 hours, the reaction mixture was quenched withmethanol (5 mL), stirred for 10 minutes and concentrated in vacuo. Theresidue was purified by silica gel chromatography (Gradient: 40-100%ethyl acetate in heptane, then 0-12% methanol in ethyl acetate) toafford C21 as a solid. Yield: 3.85 g, 3.66 mmol, 41%. LCMS m/z 1051.4(M+1). ¹H NMR (400 MHz, DMSO-d₆) δ 1.38 (s, 9H), 1.39 (s, 6H), 1.46 (s,9H), 3.3 (obscured by HOD signal), 3.66 (m, 1H), 3.70 (dd, J=6.3, 6.3Hz, 1H), 4.00-4.13 (m, 2H), 4.56 (m, 1H), 4.93 (m, 2H), 5.29 (s, 2H),5.30 (s, 2H), 7.25 (s, 1H), 7.31-7.50 (m, 10H), 7.57 (s, 1H), 8.35 (s,1H), 9.02 (d, J=8.5 Hz, 1H), 11.84 (br s, 1H).

B. Preparation of C22. A solution of C21 (0.460 g, 0.438 mmol) intetrahydrofuran (10 mL) and acetic acid (0.1 mL) was degassed andflushed with nitrogen (3×) and treated with Pd black (134 mg). Themixture was hydrogenated using a Parr shaker under 36 psi hydrogen atroom temperature for 4 hours (reaction complete by LCMS). The sample wasfiltered through acid washed cellulose powder and washed with THF togive a pale red filtrate, which was concentrated to dryness in vacuoaffording 0.382 g (100%) as a red solid. LCMS m/z 871.8 (M+1). ¹H NMR(500 MHz, DMSO-d₆) δ 1.39 (s, 9H), 1.40 (s, 6H), 1.46 (s, 9H), 3.29 (m,2H), 3.39 (dd, J=6.3, 3.3 Hz, 1H), 3.65 (HOD lump obscures signal), 3.71(m, 1H, estimated), 3.94 (m, 2H, estimated), 4.92 (m, 1H), 7.26 (s, 1H),7.39 (s, 1H), 8.02 (s, 1H), 9.01 (d, J=8.0 Hz, 1H), 11.82 (br s, 1H).

Step 3. Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({4-[(2R)-2,3-dihydroxypropyl]-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid, disodium salt (3)

A. Preparation of compound 3. Trifluoroacetic acid (13 mL) was added toa cooled (0° C.) solution of C22 (2.54 g, 2.91 mmol) in 13 mL ofdichloromethane. The reaction mixture was stirred at room temperaturefor 2 hours and then transferred slowly via a teflon cannula to anotherround bottom flask containing 186 mL of a 2:1 mixture ofheptane/methyl-t-butyl ether (MTBE) resulting in a fine precipitate. Thesolids were collected by filtration, washed with heptane/MTBE (2:1) anddried in vacuo affording 1.82 g (88%) of the trifluoroacetic acid saltof 3 as a rose colored solid. A portion of this material (2.42 g) wasthen purified by reverse phase chromatography using an Isco RfChromatography system employing a RediSep® Rf C18 column (130 g),loading the crude trifluoroacetic acid salt as a solution indimethylsulfoxide (1.5 mL) in two batches. The gradient was 5% to 30%water (0.1% Formic acid)/acetonitrile (0.1% Formic acid). The productcame off the column at 15-18% acetonitrile. The fractions were pooledand the solvent was removed under reduced pressure affording 0.847 g(35%) of material as a white solid. The solid was sonicated in methanol(4 times) and solvent was removed (done to remove formic acid). The ¹HNMR confirms the free-form product with a minimal amount of formic acid.LCMS m/z 715.0 (M+1). ¹H NMR (500 MHz, DMSO-d₆) δ 1.42 (s, 3H), 1.43 (s,3H), 3.28 (m, 2H), 3.38 (dd, J=6.3, 3.4 Hz, 1H), 3.65 (m, 1H), 3.70 (m,1H), 3.95 (br d, J=6.5 Hz, 2H), 4.91 (m, 1H), 6.79 (s, 1H), 7.36 (s,1H), 8.01 (s, 1H), 9.03 (d, J=8.3 Hz, 1H). To a slurry of 1.20 g (1.65mmol) of the free-form acid in 30 mL of deionized water at 0° C. wasslowly added 0.277 g (3.30 mmol) of sodium bicarbonate dissolved in 6 mLof deionized water (solids completely dissolve upon addition of thesodium bicarbonate solution). The resulting solution was then frozen andlyophilized affording 1.12 g of the disodium salt as a light pinklyophile. LCMS m/z 715.6 (M+1). ¹H NMR (500 MHz, D₂O) δ 1.31 (s, 3H),1.32 (s, 3H), 3.44 (dd, % ABX, J=12.1 Hz, 4.8 Hz, 1H), 3.48 (dd, % ABX,J=11.8 Hz, 4.0 Hz, 1H), 3.65 (dd, J=7.3 Hz, 3.3 Hz, 1H), 3.73-3.92 (m,3H), 4.90 (dd, J=3.2 Hz, 3.2 Hz, 1H), 6.79 (s, 1H), 6.97 (s, 1H), 7.72(s, 1H).

Example 4 Preparation of2-({[(1Z)-2-{[(3S)-1-({[4-(2-amino-2-oxoethyl)-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2-oxoazetidin-3-yl]amino}-1-(2-amino-1,3-thiazol-4-yl)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid, disodium salt (4)

Compound 4 was prepared by the procedures depicted in Schemes 11 to 13and described in detail below.

Step 1. Preparation of{3-[4,5-bis(benzyloxy)pyridin-2-yl]-5-oxo-1,5-dihydro-4H-1,2,4-triazol-4-yl}acetonitrile(C24)

A. Preparation of2-{[4,5-bis(benzyloxy)pyridin-2-yl]carbonyl}-N-(cyanomethyl)hydrazinecarboxamide(C23). Aminoacetonitrile (0.11 g, 1.92 mmol) and triethylamine (0.162 g,1.60 mmol) were added drop-wise over one minute to a suspension of C6(0.60 g, 1.6 mmol) in tetrahydrofuran (5 mL), and the mixture was heatedto 55° C. for 20 hours. Additional aminoacetonitrile (0.108 g, 1.92mmol) and triethylamine (0.162 g, 1.60 mmol) were added and heating wascontinued at 55° C. for 20 hours. After being cooled to 0° C. with anice-bath, the suspension was filtered, and the solid was washed withtetrahydrofuran, and dried under vacuum to afford C23 as a solid. Yield:0.550 g, 1.27 mmol, 79%. LCMS m/z 430.3 (M−1). ¹H NMR (400 MHz, DMSO-d₆)δ 4.00 (d, J=5.5 Hz, 2H), 5.33 (s, 2H), 5.34 (s, 2H), 7.30-7.48 (m,10H), 7.70 (s, 1H), 8.27 (s, 1H), 8.38 (br s, 1H), 10.18 (br s, 1H).

B. Preparation of C24 (Cyclization Method 2).2,2,2-Trifluoro-N-methyl-N-(trimethylsilyl)acetamide (MSTFA, 98%, 8 mL,37 mmol) and C23 (0.310 g, 0.728 mmol), were combined in a microwavetube and heated to 150° C. for 15 minutes. This process was repeated sixtimes for a combined total of 2.20 g of C23 employed. The reactions werecombined and concentrated in vacuo, and the residue was purified bysilica gel chromatography (Gradient: 30-50% ethyl acetate in heptane) toafford C24 as a solid. Yield: 1.1 g, 2.66 mmol, 52%. LCMS m/z 414.2(M+1). ¹H NMR (400 MHz, DMSO-d₆) δ 5.17 (s, 2H), 5.32 (s, 2H), 5.34 (s,2H), 7.29-7.50 (m, 10H), 7.64 (s, 1H), 8.36 (s, 1H), 12.34 (s, 1H).

Step 2. Preparation of tert-butyl2-({[(1Z)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-{[(3S)-1-({[4-(cyanomethyl)-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2-oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2-methylpropanoate(C26)

A. Preparation of tert-butyl2-({[(1Z)-2-({(3S)-1-[({3-[4,5-bis(benzyloxy)pyridin-2-yl]-4-(cyanomethyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbarnoyl]-2-oxoazetidin-3-yl}amino)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-oxoethylidene]amino}oxy)-2-methylpropanoate(C25). Compound C25 was prepared according to the general procedure forthe synthesis of C21 in Example 3, except that C24 was used in place ofC20. The crude material was purified by silica gel chromatography(Gradient: 35-75% ethyl acetate in heptane) to afford C25. Yield: 1.64g, 1.61 mmol, 21%. This material was used in the next step withoutfurther purification. LCMS m/z 1016.5 (M+1).

B. Compound C26. Compound C26 was prepared according to the generalprocedure for the synthesis of C22 in Example 3, except that C25 wasused in place of C21, and the reaction was hydrogenated at 25 psi for1.5 hours to afford C19 as a brown solid. Yield: 0.635 g, 0.759 mmol,98%. LCMS m/z 836.3 (M+1).

Step 3. Preparation of 4

A. Preparation of2-({[(1Z)-2-{[(3S)-1-({[4-(2-amino-2-oxoethyl)-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2-oxoazetidin-3-yl]amino}-1-(2-amino-1,3-thiazol-4-yl)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid (C27). Compound C27 was prepared according to the general procedurefor the synthesis of 3 in Example 3, except that C26 was used in placeof C22. Also, the crude trifluoroacetic acid salt of compound 4 wasgenerated by evaporation of the trifluoroacetic acid/dichloromethanesolution as opposed to using the precipitation technique employed inexample 3. The crude product was dissolved in dimethyl sulfoxide to aconcentration of 100 mg/mL, filtered, and purified by preparative HPLC(column: Waters Symmetry C8, 5 μm, 30×50 mm; Solvent A: 0.1% aqueousformic acid; Solvent B: 0.1% formic acid in acetonitrile. Gradient: 3%to 22% B). The fractions that pertained to the desired product werecombined, cooled to −78° C. and lyophilized to provide C27 as a pinksolid. Yield: 0.078 g, 0.11 mmol, 12%. LCMS m/z 698.9 (M+1). ¹H NMR (400MHz, DMSO-d₆) δ 1.38 (br s, 6H), 3.33 (m, 1H), 3.65 (m, 1H), 4.61 (s,2H), 4.88 (m, 1H), 6.74 (br s, 1H), 7.03 (br s, 1H), 7.30 (s, 1H), 7.89(s, 1H), 8.99 (d, J=7.42 Hz, 1H).

B. Preparation of 4. A solution of C27 (78 mg, 0.11 mmol) in a mixtureof acetonitrile (5 mL) and water (45 mL) was cooled to 0° C. and sodiumbicarbonate (18.8 mg, 0.224 mmol) was added. The mixture was vigorouslystirred for ten minutes at 0° C. The suspension was then cooled to −78°C. (using a dry ice/acetone bath) and lyophilized to afford 4 as a pinksolid. Yield: 0.079 g, 0.106 mmol, 95%. ¹H NMR (400 MHz, DMSO-d₆) δ 1.42(s, 3H), 1.50 (s, 3H), 3-3.5 ppm obscured by water peak, 3.78 (m, 1H),4.57 (d, J=16.4 Hz, 1H), 4.72 (d, J=16.4 Hz, 1H), 5.15 (m, 1H), 6.78 (s,1H), 6.99 (br. s, 1H), 7.18 (br s, 3H), 7.38 (br s, 1H), 7.41 (s, 1H),7.81 (s, 1H).

Example 5 Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({4-[(2S)-2,3-dihydroxypropyl]-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid, disodium salt (5)

Compound 5 was prepared by the procedures depicted in Schemes 14 to 16and described in detail below.

Step 1. Preparation of5-[4,5-bis(benzyloxy)pyridin-2-yl]-4-[(2S)-2,3-dihydroxypropyl]-2,4-dihydro-3H-1,2,4-triazol-3-one(C29)

A. Preparation of2-{[4,5-bis(benzyloxy)pyridin-2-yl]carbonyl}-N-[(2S)-2,3-dihydroxypropyl]hydrazinecarboxamide(C28). Compound C28 was prepared according to the general procedure forthe synthesis of C19 in Example 3, except that(2S)-3-aminopropane-1,2-diol was used in place of(2R)-3-aminopropane-1,2-diol. Compound C28 was obtained as a yellowsolid. Additional product was obtained by removing the solvent from thefiltrate in vacuo to afford a yellow solid (8.58 g), which was slurriedin tetrahydrofuran (50 mL), heated to reflux and then filtered to afforda second crop of C28. The combined yield for C28 was 16.73 g, 35.88mmol, 90%. LCMS m/z 467.2 (M+1). ¹H NMR (500 MHz, DMSO-d₆) δ 2.91 (m,1H), 3.20 (m, 1H), 3.28 (m, 2H), 3.44 (m, 1H), 5.31 (s, 2H), 5.32 (s,2H), 6.49 (m, 1H), 7.31-7.48 (m, 10H), 7.69 (s, 1H), 8.25 (s, 1H),

B. Preparation of C29. Compound C29 was prepared according to thegeneral procedure for the synthesis of C20 in Example 3, except that C28was used in place of C19. The crude product was heated with methanol(100 mL), the hot mixture was filtered, and the filtrate concentrated to20 mL. The resulting solid was collected by filtration to afford C29.Yield: 150 mg, 0.334 mmol, 22%. LCMS m/z 449.2 (M+1). ¹H NMR (400 MHz,DMSO-d₆) δ 3.28 (m, 2H), 3.70 (m, 1H), 4.09 (t, J=5.8 Hz, 1H), 5.01 (d,J=5.4 Hz, 1H), 5.27 (s, 2H), 5.31 (s, 2H), 7.32-7.49 (m, 10H), 7.58 (s,1H), 8.32 (s, 1H), 12.03 (br s, 1H).

Step 2. Preparation of tert-butyl2-({[(1Z)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-({(3S)-1-[({4-[(2S)-2,3-dihydroxypropyl]-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoate(C31)

A. Preparation of tert-butyl2-({[(1Z)-2-({(3S)-1-[({3-[4,5-bis(benzyloxy)pyridin-2-yl]-4-[(2S)-2,3-dihydroxypropyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbarnoyl]-2-oxoazetidin-3-yl}arnino)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-oxoethylidene]amino}oxy)-2-methylpropanoate(C30). Compound C30 was prepared according to the general procedure forthe synthesis of C21 in Example 3, except that C29 was used in place ofC20. After the reaction was quenched with methanol and concentrated invacuo, the residue was purified by silica gel chromatography (Gradient:25-100% ethyl acetate in heptane, then 0-7% methanol in ethyl acetate)to afford C30 as a solid. Yield: 5.41 g, 5.14 mmol, 53%. LCMS m/z 1051.7(M+1). ¹H NMR (400 MHz, DMSO-d₆) δ 1.38 (s, 9H), 1.40 (s, 3H), 1.40 (s,3H), 1.46 (s, 9H), 3.28 (m, 2H), 3.39 (dd, J=6.1, 3.2 Hz, 1H), 3.68 (m,2H), 4.03 (m, 1H), 4.11 (m, 1H), 4.92 (m, 1H), 5.28 (s, 2H), 5.30 (s,2H), 7.25 (s, 1H), 7.31-7.50 (m, 10H), 7.58 (s, 1H), 8.35 (s, 1H), 9.00(d, J=8.3 Hz, 1H).

B. Preparation of C31. Compound C31 was prepared according to thegeneral procedure for the synthesis of C22 in Example 3, except that C30was used in place of C21, and the reaction was hydrogenated at 25 psifor 1.5 hour to afford C31 as a red solid. Yield: 3.49 g, 4.00 mmol,95%. LCMS m/z 871.6 (M+1).

Step 3. Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({4-[(2S)-2,3-dihydroxypropyl]-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid, disodium salt (5)

A. Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({4-[(2S)-2,3-dihydroxypropyl]-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid C32. Compound C32 was prepared according to the general procedurefor the synthesis of 3 in Example 3, except that C31 was used in placeof C22. The crude product was dissolved in dimethyl sulfoxide to aconcentration of 100 mg/mL, filtered, and purified by preparative HPLC(column: Waters® Symmetry C8, 5 μm, 30×50 mm; Solvent A: 0.1% aqueousformic acid; Solvent B: 0.1% formic acid in acetonitrile. Gradient: 3%to 23% B). The fractions that pertained to the desired product wereconcentrated in vacuo, keeping the water bath <30° C., to provide asolid. This solid was dissolved in a mixture of acetonitrile (10 mL) andwater (100 mL), cooled to −78° C. and lyophilized to provide C32 as apink solid. Yield: 0.155 g, 0.217 mmol, 9%. LCMS m/z 715.2 (M+1). ¹H NMR(500 MHz, DMSO-d₆) δ 1.42 (s, 3H), 1.43 (s, 3H), 3.27 (m, 2H), 3.37 (dd,J=6.1, 3.1 Hz, 1H), 3.65 (m, 1H), 3.70 (m, 1H), 3.95 (m, 2H), 4.91 (m,1H), 6.81 (s, 1H), 7.37 (s, 1H), 8.01 (s, 1H), 9.04 (d, J=8.3 Hz, 1H).HPLC analysis: Hewlett Packard 1100; Column: Waters® Symmetry C8, 5 μM,4.6×50 mm; Flow rate 1.2 mL/min; Solvent A: 0.1% aqueous formic acid;Solvent B: 0.1% formic acid in acetonitrile; Gradient: 5% to 100% B over6 minutes; Injection volume: 15 uL; Detection: 254 nm; Retention time:3.46 min.

B. Preparation of compound 5. Compound 5 was prepared according to thegeneral procedure for the synthesis of 4 in Example 4, except that C32was used in place of C27, to afford 5 as a pink solid. Yield: 0.155 g,0.204 mmol, 97%. LCMS m/z 715.2 (M+1). ¹H NMR (500 MHz, D₂O) δ 1.40 (s,3H), 1.42 (s, 3H), 3.49 (dd, half of an ABX pattern, J=12.2, 4.9 Hz,1H), 3.57 (dd, half of an ABX pattern J=12.2, 3.7 Hz, 1H), 3.74 (m, 1H),3.88 (m, 1H), 3.98 (m, 3H), 5.03 (m, 1H), 6.90 (s, 1H), 7.02 (s, 1H),7.80 (s, 1H). HPLC analysis: Hewlett Packard 1100; Column: Waters®Symmetry C8, 5 μM, 4.6×50 mm; Flow rate 1.2 mL/min; Solvent A: 0.1%aqueous formic acid; Solvent B: 0.1% formic acid in acetonitrile;Gradient: 5% to 100% B over 6 minutes; Injection volume: 15 uL;Detection: 254 nm; Retention time: 3.44 min.

Example 6 Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-4-[(2R)-2-hydroxypropyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidenelamino}oxy)-2-methylpropanoicacid, disodium salt. (6)

Compound 6 was prepared by the procedures depicted in Schemes 17 to 19and described in detail below.

Step 1. Preparation of5-[4,5-bis(benzyloxy)pyridin-2-yl]-4-[(2R)-2-hydroxypropyl]-2,4-dihydro-3H-1,2,4-triazol-3-one(C34)

A. Preparation of2-{[4,5-bis(benzyloxy)pyridin-2-yl]carbonyl}-N-[(2R)-2-hydroxypropyl]hydrazinecarboxamide(C33). Compound C33 was prepared according to the general procedure forthe synthesis of C19 in Example 3, except that (2R)-1-aminopropan-2-olwas used in place of (2R)-3-aminopropane-1,2-diol, and the reaction washeated for 60 hours, to provide C33 as a white solid. Yield: 4.54 g,10.1 mmol, 84%. LCMS m/z 451.2 (M+1). ¹H NMR (400 MHz, DMSO-d₆) δ 1.00(d, J=6.2 Hz, 3H), 2.91 (m, 1H), 3.01 (m, 1H), 3.61 (m, 1H), 4.64 (d,J=4.7 Hz, 1H), 5.33 (br s, 4H), 6.28 (dd, J=5.8 Hz, 1H), 7.31-7.49 (m,10H), 7.69 (s, 1H), 7.93 (br s, 1H), 8.28 (s, 1H), 9.97 (br s, 1H).

B. Preparation of C34. Compound C34 was prepared according to thegeneral procedure for the synthesis of C20 in Example 3, except that C33was used in place of C19. After the solid was filtered, it wasrecrystallized from methanol (250 mL) to obtain two combined crops ofC34. Yield: 36.5 g, 84.4 mmol, 74%. LCMS m/z 433.6 (M+1). ¹H NMR (400MHz, DMSO-d₆) δ 0.98 (d, J=6.3 Hz, 3H), 3.81 (m, 1H), 3.96 (dd, half ofan ABX pattern, J=13.3, 5.3 Hz, 1H), 4.05 (dd, half of an ABX pattern,J=13.3, 7.4 Hz, 1H), 4.84 (d, J=5.1 Hz, 1H), 5.28 (s, 2H), 5.31 (s, 2H),7.32-7.49 (m, 10H), 7.59 (s, 1H), 8.32 (s, 1H), 11.96 (br s, 1H).

Step 2. Preparation of tert-butyl2-({[(1Z)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-4-[(2R)-2-hydroxypropyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoate(C36)

A. Preparation of tert-butyl2-({[(1Z)-2-({(3S)-1-[({3-[4,5-bis(benzyloxy)pyridin-2-yl]-4-[(2R)-2-hydroxypropyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-oxoethylidene]amino}oxy)-2-methylpropanoate(C35). A suspension of C34 (1 g, 2.31 mmol) in1,1,1,3,3,3,-hexamethyldisilazane (2.54 mL, 11.6 mmol) was treated withtrimethylsilyl chloride (0.002 mL, 0.012 mmol), and the mixture washeated at 140° C. for 2 hours. The yellow solution was then cooled toroom temperature and concentrated in vacuo to afford a yellow gum. In aseparate flask, a suspension of C13 (1.15 g, 2.31 mmol) indichloromethane (2 mL) under nitrogen at 0° C. was treated withcarbonylsulfamoyl chloride (0.211 mL, 2.31 mmol) and stirred for 1.5hours at 0° C. The mixture became a homogenous solution. The materialderived from C34 was treated with dichloromethane (2 mL), and theresulting yellow solution was cooled to −40° C. and stirred undernitrogen. The ice-cooled C13-containing reaction mixture was transferredinto this solution via syringe. The mixture was stirred at −40° C. for30 minutes, warmed to room temperature over 1 hour and stirred for 2hour at room temperature. The mixture was quenched by the addition ofmethanol (5 mL), the solvent was removed in vacuo, and the crudematerial was purified by silica gel chromatography (Gradient: 0-3%methanol in ethyl acetate) to afford C35 as a solid. Yield: 1.42 g, 1.37mmol, 59%. LCMS m/z 1035.7 (M+1) ¹H NMR (400 MHz, DMSO-d₆) δ 0.95 (d,J=5.8 Hz, 3H), 1.33-1.43 (m, 15H), 1.46 (s, 9H), 3.40 (m, 1H), 3.71 (m,1H), 3.77 (m, 1H), 3.95 (m, 1H), 4.06 (m, 1H), 4.84 (d, J=5.1 Hz, 1H),5.29 (s, 2H), 5.31 (s, 2H), 7.25 (s, 1H), 7.31-7.51 (m, 10H), 7.60 (s,1H), 8.36 (s, 1H), 9.02 (d, J=8.3 Hz, 1H), 11.85 (br s, 1H).

B. Preparation of C36. Compound C36 was prepared according to thegeneral procedure for the synthesis of C22 in Example 3, except that C35was used in place of C21, and the reaction was hydrogenated at 25 psifor 1.5 hour, to afford C36 as a red solid. Yield: 3.84 g, 4.49 mmol,88%. LCMS m/z 853.0 (M−1).

Step 3. Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-4-[(2R)-2-hydroxypropyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid, disodium salt (6)

A. Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-4-[(2R)-2-hydroxypropyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid C37. Compound C37 was prepared according to the general procedurefor the synthesis of 3 in Example 3, except that C36 was used in placeof C22. The crude product was dissolved in dimethyl sulfoxide to aconcentration of 100 mg/mL, filtered, and purified by preparative HPLC(column: Waters® Symmetry C8, 5 μm, 30×50 mm; Solvent A: 0.1% aqueousformic acid; Solvent B: 0.1% formic acid in acetonitrile; Gradient: 6%to 26% B). The fractions that pertained to the desired product wereconcentrated in vacuo to provide a solid, which was dissolved in amixture of acetonitrile (10 mL) and water (100 mL), cooled to −78° C.and lyophilized to provide C37 as a pink solid. Yield: 0.130 g, 0.186mmol, 15%. LCMS m/z 699.0 (M+1). ¹H NMR (500 MHz, DMSO-d₆) δ 0.97 (d,J=6.1 Hz, 3H), 1.43 (s, 3H), 1.43 (s, 3H), 3.38 (dd, J=6.3, 3.2 Hz, 1H),3.69 (dd, J=6.1, 6.1 Hz, 1H), 3.78 (m, 1H), 3.86 (m, 1H), 4.91 (m, 1H),6.83 (s, 1H), 7.39 (s, 1H), 8.02 (s, 1H), 9.08 (d, J=8.3 Hz, 1H).

B. Preparation of 6. Compound 6 was prepared according to the generalprocedure for the synthesis of 4 in Example 4, except that C37 was usedin place of C27, and that the starting material C37 was dissolved inmethanol (20 mL), sonicated for five minutes, and concentrated in vacuo.This process was repeated three times before the reaction was run.Compound 6 was obtained as a pink solid. Yield: 0.150 g, 0.202 mmol,96%. LCMS m/z 699.8 (M+1). ¹H NMR (400 MHz, DMSO-d₆) δ 0.95 (d, J=5.3Hz, 3H), 1.41 (s, 3H), 1.49 (s, 3H), 3.30-3.40 (m, 1H, assumed; obscuredby water peak) 3.82 (m, 1H), 3.97 (m, 3H), 5.11 (m, 1H), 6.78 (s, 1H),7.19 (br s, 1H), 7.36 (s, 1H), 7.88 (s, 1H).

Example 7 Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-4-[(2S)-2-hydroxypropyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid, disodium salt (7)

Compound 7 was prepared by the procedures depicted in Schemes 20 to 22and described in detail below.

Step 1. Preparation of5-[4,5-bis(benzyloxy)pyridin-2-yl]-4-[(2S)-2-hydroxypropyl]-2,4-dihydro-3H-1,2,4-triazol-3-one(C39)

A. Preparation of2-{[4,5-bis(benzyloxy)pyridin-2-yl]carbonyl}-N-[(2S)-2-hydroxypropyl]hydrazinecarboxamide(C38). Compound C38 was prepared according to the general procedure forthe synthesis of C19 in Example 3, except that (2S)-1-aminopropan-2-olwas used in place of (2R)-3-aminopropane-1,2-diol, and the reaction washeated for 12 hours, to provide C38 as a white solid. Yield: 12.56 g,27.88 mmol, 87%. LCMS m/z 451.6 (M+1). ¹H NMR (400 MHz, DMSO-d₆) δ 1.00(d, J=6.2 Hz, 3H), 2.91 (m, 1H), 3.01 (m, 1H), 3.61 (m, 1H), 4.65 (d,J=4.7 Hz, 1H), 5.33 (s, 4H), 6.28 (dd, J=5.8 Hz, 1H), 7.31-7.49 (m,10H), 7.69 (s, 1H), 7.93 (br s, 1H), 8.28 (s, 1H), 9.99 (br s, 1H).

B. Preparation of C39. Compound C39 was prepared according to thegeneral procedure for the synthesis of C20 in Example 3, except that C38was used in place of C19 and the reaction was heated for 18 hours toafford C39 as a red solid. Yield: 4.25 g, 9.82 mmol, 95%. LCMS m/z 433.3(M+1). ¹H NMR (400 MHz, DMSO-d₆) δ 0.98 (d, J=6.3 Hz, 3H), 3.85 (m, 1H),3.98 (m, 1H), 4.07 (m, 1H), 5.28 (s, 2H), 5.31 (s, 2H), 7.31-7.49 (m,11H), 7.60 (s, 1H), 8.32 (s, 1H).

Step 2. Preparation of tert-butyl2-({[(1Z)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-4-[(2S)-2-hydroxypropyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoate(C41)

A. Preparation of tert-butyl2-({[(1Z)-2-({(3S)-1-[({3-[4,5-bis(benzyloxy)pyridin-2-yl]-4-[(2S)-2-hydroxypropyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbarnoyl]-2-oxoazetidin-3-yl}amino)-1-{2-[(tert-butoxycarbonyl)amino]-1,3-thiazol-4-yl}-2-oxoethylidene]amino}oxy)-2-methylpropanoate(C40). Compound C40 was prepared according to the general procedure forthe synthesis of C35 in Example 6, except that C39 was used in place ofC34. After the mixture was quenched by the addition of methanol (3 mL),the solvent was removed in vacuo and the crude material was purified bysilica gel chromatography (Gradient: 0-3% methanol in ethyl acetate) toafford C40 as a yellow solid. Yield: 0.71 g, 0.685 mmol, 44%. LCMS m/z1035.6 (M+1). ¹H NMR (400 MHz, DMSO-d₆) δ 0.96 (d, J=6.2 Hz, 3H),1.38-1.47 (m, assumed 24H), 3.40 (dd, J=6.2, 3.1 Hz, 1H), 3.71 (m, 1H),3.78 (m, 1H), 3.95 (m, 1H), 4.07 (m, 1H), 4.83 (d, J=5.5 Hz, 1H), 4.91(m, 1H), 5.29 (s, 2H), 5.31 (s, 2H), 7.25 (s, 1H), 7.31-7.51 (m, 10H),7.60 (s, 1H), 8.36 (s, 1H), 9.01 (d, J=8.6 Hz, 1H), 11.82 (br s, 1H).

B. Preparation of C41. Compound C41 was prepared according to thegeneral procedure for the synthesis of C22 in Example 3, except that C40was used in place of C21, and the reaction was hydrogenated at 30 psifor 1 hour. Additionally, in this case filtration was carried outthrough a 1 cm bed of iron-free Celite® (Celite® was pre-washed with 1Naqueous hydrochloric acid, then with deionized water, then with acetone,and then dried). Compound C41 was obtained as a red solid. Yield: 0.630g, 0.7 mmol, 100%. LCMS m/z 855.1 (M−1).

Step 3. Preparation2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-4-[(2S)-2-hydroxypropyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid, disodium salt (7). A solution of C41 (0.630 g, 0.76 mmol) indichloromethane (0.5 mL) was cooled to 0° C. and treated withtrifluoroacetic acid (3.4 mL). The mixture was warmed to roomtemperature and stirred for 18 hours; the reaction mixture was thenslowly added drop-wise to a stirring solution of methyl-tert-butyl ether(10 mL) and heptane (20 mL). The resulting solid was filtered, dried invacuo, dissolved into dimethyl sulfoxide (1 mL) and purified via reversephase chromatography (RediSep® RF C₁₈ Column, 65 g; Solvent A: 0.1%aqueous formic acid; Solvent B: 0.1% formic acid in acetonitrile;Gradient: 5% to 25% B). The fractions that pertained to the desiredproduct were concentrated in vacuo to provide a solid. The solid wassonicated in methanol and the solvent was removed (this was carried out4 times) to give free form material as a white solid. Yield: 0.103 g,0.147 mmol, 19%. LCMS m/z 699.0 (M+1). ¹H NMR (500 MHz, DMSO-d₆) δ 0.95(d, J=6.1 Hz, 3H), 1.43 (s, 3H), 1.44 (s, 3H), 3.38 (dd, J=6.5, 3.3 Hz,1H), 3.70 (dd, J=6.1, 6.1 Hz, 1H), 3.77 (m, 1H), 3.86 (m, 2H), 4.91 (m,1H), 6.82 (s, 1H), 7.38 (s, 1H), 8.02 (s, 1H), 9.06 (d, J=8.8 Hz, 1H).Combined batches of free form (0.676 g, 0.92 mmol) were placed roundbottom flask with 10 mL of deionized water. The suspension was cooled to0° C. in an ice bath and to this mixture added (dropwise) a solution of0.154 g of sodium bicarbonate in 1.0 mL of water. The suspension wasstirred until all the solids were dissolved. The solution was thenfrozen and lyophilized affording 0.680 g of compound 7 as a light pinksolid. LCMS m/z 699.6 (M+1). ¹H NMR (500 MHz, D₂O-d₆) δ 1.01 (d, J=8.5Hz, 3H), 1.32 (d, J=6.0 Hz, 6H), 3.61-3.70 (m, 2.5H), 3.77 (dd, % ABX,J=18.5 Hz, 4.0 Hz, 0.5H), 3.88 (t, J=8.0 Hz, 1H), 4.90 (dd, J=7.5 Hz,4.5 Hz, 1H), 6.80 (s, 1H), 6.93 (s, 1H), 7.71 (s, 1H).

Example 8 Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-{(3S)-1-[({4-[(1,5-dimethyl-1H-pyrazol-3-yl)methyl]-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidenelamino}oxy)-2-methylpropanoicacid (8)

Compound 8 was prepared by the procedures depicted in scheme 23 andoutlined in detail below.

A. Preparation of C43 (Coupling Method 2). Compound C42 was prepared inan analogous manner to that described for the preparation of C8 inExample 1 affording 0.67 g (0.72 mmol) of triazalone C42 as a whitesolid. LCMS m/z 483.4 (M+1). A suspension of C42 (0.100 g, 0.207 mmol)in hexamethyldisilazide (0.227 mL, 1.04 mmol) under nitrogen at 23° C.was treated with trimethylsilylchloride (one drop, 0.13 uL, 0.001 mmol).The mixture was heated at 140° C. for 2 hours; upon heating the reactionbecame a clear brown solution. The mixture was cooled to roomtemperature and held under high vacuum for 1 hour producing a brownglass-like material. Separately, a suspension of C13 (0.103 g, 0.207mmol) in dichloromethane (0.1 mL) under nitrogen at 0° C. was treatedwith chlorosulfonylisocyanate (0.019 mL, 0.207 mmol) and stirred untilthe mixture became homogeneous (approximately 5 minutes). The solutionwas stirred for 1.5 hours at 0° C. The silylated triazolinone (0.207mmol) was treated with DCM (0.2 mL), the brown solution was cooled to−40° C. and stirred under nitrogen. The prepared sulfamoyl chloridesolution (0.1 mL, 0.207 mmol) was then transferred via syringe to thecomplex prepared from C42 and the mixture stirred at −40° C. for 30minutes, warmed to room temperature over 1 hour and stirred for 2 hoursat room temperature. The mixture was quenched by the addition ofmethanol (0.5 mL), the solvent was removed in vacuo and the crudematerial purified by column chromatography (silica-gel, 5% methanol indichloromethane) to give 0.050 g (22%) of C43. LCMS m/z 1085.1 (M+1). ¹HNMR (400 MHz, DMSO-d₆) δ 1.34-1.48 (m, 24H), 2.06-2.10 (m, 1H),2.25-2.28 (m, 1H), 3.40-3.44 (m, 1H), 3.55 (s, 1H), 4.92 (br. s, 1H),5.20-5.63 (m, 4H), 5.56-5.63 (m, 1H), 7.25 (d, J=4.9 Hz, 1H), 7.28-7.50(m, 10H), 7.58 (s, 1H), 8.33 (s, 1H), 9.01 (br. s, 2H).

B. Preparation of2-({[(1Z)-1-(2-amino-1,3-thiazol-4-yl)-2-({(3S)-1-[({4-[(1,5-dimethyl-1H-pyrazol-3-yl)methyl]-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2-oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2-methylpropanoicacid (8). Compound C43 was deprotected and HPLC purified in an analogousmanner to that described for compound 1 in Example 1 affording 0.015 g(9%) of compound 8 as a pink solid. LCMS m/z 748.9 (M+1). ¹H NMR (500MHz, DMSO-d₆) δ 1.41 (s, 3H), 1.41 (s, 3H), 2.39 (s, 1H), 3.55 (s, 3H),3.67 (m, 1H), 3.91 (dd, J=6.3, 6.3 Hz, 1H), 5.05 (m, 1H), 5.58 (s, 2H),6.73 (s, 1H), 7.26 (s, 1H), 7.34 (br s, 1H), 7.80 (s, 1H), 9.10 (d,J=8.0 Hz, 1H), 11.85 (s, 1H).

Additional Examples 9-30 are shown below in Table A and were preparedanalogously to the Examples above using either cyclization method 1(described in Example 1, step 3B) or cyclization method 2 (described inExample 4, step 1B), in combination with either coupling method 1(described in Example 1, step 6A) or coupling method 2 (described inExample 4, step 1B).

TABLE A ¹H NMR 400 MHz, DMSO-d₆ Cyclization (unless otherwise Method,indicated); Ex. Coupling Observed MS Ion No. Method Structure IUPAC Name(m/z)  9 1.1

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-5-oxo-4-propyl-4,5-dihydro-1H-1,2,4- triazol-1- yl]sulfonyl}carbamoyl)-2-oxoazetidin-3-yl]amino}-2- oxoethylidene]amino}oxy)-2- methylpropanoicacid 0.76 (t, J = 7.5 Hz, 3H), 1.42 (br s, 6H), 1.51 (m, 2H), 3.37 (dd,J = 6.2, 3.3 Hz, 1H), 3.69 (dd, J = 6.6, 6.6 Hz, 1H), 3.94 (t, J = 7.5Hz, 2H), 4.91 (m, 1H), 6.81 (s, 1H), 7.34 (s, 1H), 8.01 (s, 1H), 9.06(d, J = 7.9 Hz, 1H) 10 1.1

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[4-(2,3-dihydroxypropyl)-3-(5- hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo- 4,5-dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2- oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid 1.43 (s, 6H), 3.28 (m,2H), 3.38 (m, 1H), 3.65 (m, 1H), 3.70 (dd, J = 6.2, 6.2 Hz, 1H), 3.93(m, 2H), 4.91 (m, 1H), 6.82 (s, 1H), 7.38 (s, 1H), 8.02 (s, 1H), 9.06(d, J = 7.9 Hz, 1H); 715.5 (M + 1) 11 1.1

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-5-oxo-4-(2-pyrrolidin-1-ylethyl)-4,5- dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2- oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid Selected peaks; 1.38(s, 3H), 1.39 (s, 3H), 1.78 (m, 2H), 1.89 (m, 2H), 3.15-3.36 (m, assumed7H, obscured by water peak), 3.58 (m, 2H), 4.13 (m, 1H), 5.68 (br s,1H), 6.06 (br s, 1H), 6.86 (s, 1H), 7.30 (br s, 2H), 8.85 (br s, 1H);736.1 (M − 1) 12 1.1

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-({(3S)-1-[({4-[2-(diethylamino)ethyl]-3-(5- hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo- 4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2- oxoazetidin-3-yl} amino)-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid (MeOD) Selected peaks:1.27-1.35 (m, assumed 6H), 1.55 (s, 3H), 1.56 (s, 3H), 3.39 (m, 4H),3.59 (dd, J = 6.6. 6.6 Hz, 1H), 3.66 (t, J = 5.4 Hz, 2H), 3.92(dd, J =6.6, 6.6 Hz, 1H), 4.51 (t, J = 5.4 Hz, 2H), 5.34 (m, 1H), 6.89 (s, 1H),7.50 (s, 1H), 8.05 (s, 1H); 740.5 (M + 1) 13 2.1

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-5-oxo-4-(2,2,2-trifluoroethyl)-4,5- dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2- oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid 1.41 (s, 3H), 1.41 (s,3H), 3.36 (dd, J = 6.2, 3.2 Hz, 1H), 3.69 (dd, J = 6.2, 6.2 Hz, 1H),4.91 (m, 1H), 5.11 (m, 2H), 6.76 (s, 1H), 7.37 (s, 1H), 8.00 (s, 1H),9.01 (d, J = 8.3 Hz, 1H); 723.1 (M + 1) 14 2.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[4-(3,3-dimethylbutyl)-3-(5- hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol- 1-yl]sulfonyl}carbamoyl)-2-oxoazetidin-3-yl]amino}-2- oxoethylidene]amino}oxy)-2- methylpropanoicacid 0.89 (s, 9H), 1.40 (m, 2H), 1.43 (s, 3H), 1.43 (s, 3H), 3.37 (dd, J= 6.4, 3.1 Hz, 1H), 3.70 (dd, J = 6.4, 6.4 Hz, 1H), 4.01 (m, 2H), 4.92(m, 1H), 6.80 (s, 1H), 7.99 (s, 1H), 9.05 (br d, J = 8.8 Hz, 1H); 725.2(M + 1) 15 1.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-4-(2-methoxyethyl)-5-oxo-4,5- dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2- oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid, disodium salt 1.42 (s,3H), 1.50 (s, 3H), 3.16 (s, 3H), 3.32 (HOD, obscures region), 3.48 (m,2H), 3.78 (dd, J = 6.3, 6.3 Hz, 1H), 4.18 (m, 2H), 5.14 (m, 1H), 6.79(s, 1H), 7.19 (br s, 2H), 7.40 (s, 1H), 7.88 (s, 1H); 699.2 (M + 1) 161.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-5-oxo-4-[(2S)-tetrahydrofuran-2- ylmethyl]-4,5-dihydro-1H- 1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2- oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid Selected peaks: 1.42(br s, 6H), 3.38 (m, 1 H), 3.48 (t, J = 5.1, 2 H), 3.70 (dd, J = 6.2,6.2, 2H), 3.97 (m, 2H), 4.13 (m, 1 H), 4.92 (m, 1 H), 6.82 (s, 1 H),7.35 (s, 1 H), 8.01 (s, 1H), 9.04 (d, J = 8.0 Hz, 1H); 725.2 (M + 1) 171.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-4-(3-hydroxypropyl)-5-oxo-4,5- dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2- oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid (500 MHz) 1.44 (s, 3H),1.44 (s, 3H), 1.67 (m, 2H), 3.35 (t, J = 6.3 Hz, 2H), 3.38 (dd, J = 6.5,3.3 Hz, 1H), 3.70 (dd, J = 6.4, 6.4 Hz, 1H), 4.01 (m, 2H), 4.92 (m, 1H),6.84 (s, 1H), 7.35 (s, 1H), 8.01 (s, 1H), 9.07 (d, J = 8.5 Hz, 1H);699.0 (M + 1) 18 1.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[4-(2-hydroxyethyl)-3-(5- hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol- 1-yl]sulfonyl}carbamoyl)-2-oxoazetidin-3-yl]amino}-2- oxoethylidene]amino}oxy)-2- methylpropanoicacid (500 MHz) 1.40(s, 3H), 1.41 (s, 3H), 3.29-3.38 (m, assumed 4H,obscured by water peak), 3.47 (m, 1H), 4.08 (dd, J = 6.3, 6.3, 1H), 4.89(m, 1 H), 6.54 (s, 1H), 6.71 (s, 1H), 7.31 (m, 2H), 8.00 (s, 1H), 9.06(m, 1H); 685.0 (M + 1) 19 1.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({(3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-5-oxo-4-(tetrahydro-2H-pyran-4- ylmethyl)-4,5-dihydro-1H- 1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2- oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid 1.11 (m, 2H), 1.39 (m,2H), 1.42 (s, 3H), 1.43 (s, 3H), 1.84 (m, 1H), 3.15 (m, 2H), 3.36 (dd, J= 6.4, 3.5 Hz, 1H), 3.68 (dd, J = 6.2, 6.2 Hz, 1H), 3.75 (br d, J = 10Hz, 2H), 3.97 (d, J = 6.8 Hz, 2H), 4.91 (m, 1H), 6.79 (s, 1H), 7.36 (s,1H), 8.01 (s, 1H), 9.02 (d, J = 8.4 Hz, 1H); 739.2 (M + 1) 20 1.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-5-oxo-4-[3-(2-oxopyrrolidin-1- yl)propyl]-4,5-dihydro-1H- 1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2- oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid 1.44 (s, 6H), 1.74 (m,2H), 1.91 (m, 2H), 2.19 (t, J = 8.1 Hz, 2H), 3.17 (t, J = 6.9 Hz, 2H),3.31 (t, J = 6.9 Hz, 2H), 3.37 (dd, J = 6.6, 3.3 Hz, 1H), 3.70 (dd, J =6.2, 6.2 Hz, 1H), 3.94 (m, 2H), 4.92 (m, 1H), 6.84 (s, 1H), 7.36 (s,1H), 8.01 (s, 1H), 9.05 (d, J = 8.8 Hz, 1H); 766.2 (M + 1) 21 1.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-5-oxo-4-[2-(2-oxoimidazolidin-1- yl)ethyl]-4,5-dihydro-1H- 1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2- oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid Product peaks: 1.41 (s,3H), 1.41 (s, 3H), 3.29-3.56 (m, assumed 4H, obscured by water peak),3.77 (m, 1H), 3.82 (m, 2H), 4.15 (t, J = 6.6, 2H), 5.00 (m, 1H), 6.72(s, 1H), 7.32 (s, 1H), 8.01 (s, 1H), 8.99 (d, J = 8.2 Hz, 1H); 753.2(M + 1) 22 1.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[4-(2-ethoxyethyl)-3-(5-hydroxy- 4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H- 1,2,4-triazol-1- yl]sulfonyl}carbamoyl)-2-oxoazetidin-3-yl]amino}-2- oxoethylidene]amino}oxy)-2- methylpropanoicacid 0.93 (t, J = 6.9 Hz, 3H), 1.44 (s, 6H), 3.31 (q, J = 6.9 Hz, 2H),3.37 (m, 1H), 3.46 (t, J = 5.7 Hz, 2H), 3.70 (dd, J = 5.9, 5.9 Hz, 1H),4.14 (m, 2H), 4.92 (m, 1H), 6.82 (s, 1H), 7.36 (s, 1H), 8.01 (s, 1H),9.04 (d, J = 8.6 Hz, 1H); 713.2 (M + 1) 23 1.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-5-oxo-4-[(2R)-tetrahydrofuran-2- ylmethyl]-4,5-dihydro-1H- 1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2- oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid Selected peaks: 1.42(br s, 6H), 3.36 (m, 1 H), 3.48 (t, J = 5.3 Hz, 2 H), 3.70 (dd, J = 6.2,6.2 Hz, 1H), 3.97 (m, 2H), 4.14(m, 1 H), 4.91 (m, 1 H), 6.78 (br s, 1H), 7.34 (s, 1 H), 8.01 (s, 1H), 9.02 (d, J = 7.8 Hz, 1H) 24 2.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[4-(2-hydroxy-2-methylpropyl)- 3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo- 4,5-dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2- oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid 1.00 (s, 6H), 1.42 (s,6H), 3.37 (m, 1H), 3.69 (dd, J = 6.2, 6.2 Hz, 1H), 3.96 (s, 2H), 4.91(m, 1H), 6.75 (s, 1H), 7.31 (s, 1H), 7.98 (s, 1H), 8.98 (d, J = 8.6 Hz,1H); 713.2 (M + 1) 25 1.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[4-(3-ethoxy-2-hydroxypropyl)- 3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)-5-oxo- 4,5-dihydro-1H-1,2,4-triazol-1-yl]sulfonyl}carbamoyl)-2- oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid 1.05 (t, J = 6.9 Hz,3H), 1.43 (s, 3H), 1.43 (s, 3H), 3.25 (d, J = 5.3 Hz, 2H), 3.36 (q, J =6.9 Hz, 2H), 3.39 (m, 1H), 3.70 (dd, J = 6.2, 6.2 Hz, 1H), 3.79 (m, 1H),3.97 (m, 2H), 4.91 (m, 1H), 6.80 (s, 1H), 7.36 (s, 1H), 8.00 (s, 1H),9.03 (d, J = 8.4 Hz, 1H); 743.2 (M + 1) 26 1.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-({(3S)-1-[({4-[(1R)-2-hydroxy-1- methylethyl]-3-(5-hydroxy-4-oxo-1,4-dihydropyridin-2-yl)- 5-oxo-4,5-dihydro-1H-1,2,4- triazol-1-yl}sulfonyl)carbamoyl]-2- oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid (500 MHz) 1.35 (d, J =6.8 Hz, 3H), 1.43 (s, 3H), 1.44 (s, 3H), 3.39 (dd, J = 6.3, 3.2 Hz, 1H),3.50 (dd, J = 10.9, 5.5 Hz, 1H), 3.71 (dd, J = 6.3. 6.3 Hz, 1H), 3.82(dd, J = 10.9, 8.9 Hz, 1H), 4.65 (m, 1H), 4.92 (m, 1H), 6.83 (s, 1H),7.32 (s, 1H), 8.04 (s, 1H), 9.07 (d, J = 8.3 Hz, 1H); 699.0 (M + 1) 271.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-4-[(5-methylisoxazol-3-yl)methyl]- 5-oxo-4,5-dihydro-1H-1,2,4- triazol-1-yl}sulfonyl)carbamoyl]-2- oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid 1.42 (s, 6H), 2.30 (s,3H), 3.38 (m, 1H), 3.42-3.74(m, assume 1 H, obscured by water peak),4.92 (m, 1H), 5.35 (s, 2H), 6.05 (s, 1H), 6.78 (s, 1H), 7.35 (s, 1H),7.93 (s, 1H), 9.01 (d, J = 8.0 Hz, 1H); 736.1 (M + 1) 28 2.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[4- (3-hydroxy-2,2-dimethylpropyl)-3-(5-hydroxy- 4-oxo-1,4-dihydropyridin-2-yl)-5-oxo-4,5-dihydro-1H- 1,2,4-triazol-1- yl]sulfonyl}carbamoyl)-2-oxoazetidin-3-yl]amino}-2- oxoethylidene]amino}oxy)-2- methylpropanoicacid 0.58 (s, 6H), 1.43 (s, 3H), 1.44 (s, 3H), 2.97 (s, 2H), 3.38 (dd, J= 6.3, 3.2 Hz, 1H), 3.70 (dd, J = 6.3, 6.3 Hz, 1H), 4.05 (s, 2H), 4.92(m, 1H), 6.83 (s, 1H), 7.28 (s, 1H), 8.02 (s, 1H), 9.05 (d, J = 8.4 Hz,1H); 726.9 (M + 1) 29 1.1

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-({(3S)-1-[({3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-4-[2-(3-methylphenyl)ethyl]-5-oxo- 4,5-dihydro-1H-1,2,4-triazol-1-yl}sulfonyl)carbamoyl]-2- oxoazetidin-3-yl}amino)-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid Selected peaks: 1.40(s, 9H), 2.74 (t, J = 7.5 Hz, 2H), 4.13 (t, J = 8.1 Hz, 2H), 4.86- 4.92(m, 1H), 6.78- 6.95 (m,3H), 7.07 (t, J = 7.8 Hz, 1H), 7.12 (s, 1H), 8.01(s, 1H), 9.05 (d, J = 7.8 Hz, 1H); 759.2 (M + 1) 30 2.2

2-({[(1Z)-1-(2-amino-1,3- thiazol-4-yl)-2-{[(3S)-1-({[3-(5-hydroxy-4-oxo-1,4- dihydropyridin-2-yl)-4-(2-methoxy-1-methylethyl)-5- oxo-4,5-dihydro-1H-1,2,4- triazol-1-yl]sulfonyl}carbamoyl)-2- oxoazetidin-3-yl]amino}-2-oxoethylidene]amino}oxy)-2- methylpropanoic acid 1.36 (d, J = 6.5 Hz,3H), 1.44 (d, J = 3.0 Hz, 6H), 3.38 (dd, J = 6.1 Hz, 3.0 Hz, 1H), 3.41(dd, J = 10.0 Hz, 5.6 Hz, 1H), 3.71 (t, J = 6.5 Hz, 2H), 3.86 (t, J =10.0 Hz, 2H), 4.90- 4.95 (m, 1H), 5.03 (br. s, 1H), 6.83 (s, 1H), 7.29(s, 1H), 8.03 (s, 1H), 9.08 (d, J = 8.7 Hz, 1H); 713.2 (M + 1)

Biological Properties

In some embodiments, compounds of the invention exhibit a targeted andeffective activity against bacteria. Compounds of the invention cantherefore be used, e.g., for treating and/or preventing a variety ofdiseases caused by pathogenic bacteria in human beings and animals.

Table 1 below shows in vitro MIC data for specified strains ofPseudomonas aeruginosa, Klebsiella pneumonia, and Acinetobacterbaumanii. Culture collection strain 1045-06 is resistant to severalclasses of known antimicrobial agents including carbapenems,aminoglycosides and fluoroquinolones, while strains 1000-02 and 3167 areresistant to cephalosporins. Strain PA0200 is a derivative of laboratorystrain PAO1 that lacks a functional MexAB-oprM efflux pump. Thecompounds listed are highly active against all three of these screeningstrains demonstrating their broad activity against gram-negativebacterial pathogens.

TABLE 1 MIC of Examples 1-30 MIC MIC MIC MIC Pseudomonas PseudomonasKlebsiella Acinetobacter aeruginosa aeruginosa pneumoniae baumaniiPA0200 MexAB- Ex. 1045-06 1000-02 3167 oprM KO No. (mg/mL) (mg/mL)(mg/mL) (mg/mL) 1 N.T. N.T. N.T. <0.0625 2 N.T. N.T. N.T. 0.188¹ 3 0.50.5 0.5 N.T. 4 0.5 1 1 N.T. 5 0.25 0.5 0.5 N.T. 6 0.25 0.5 1 N.T. 7 0.250.25 1 N.T. 8 32 8 >64.0 N.T. 9 N.T. N.T. N.T. <0.0625 10 N.T. N.T. N.T.0.25¹ 11 N.T. N.T. N.T. 16 12 2 2 16 N.T. 13 0.25 0.25 16 N.T. 14 0.50.06 2 N.T. 15 0.5 0.5 4 N.T. 16 0.5 0.5 2 N.T. 17 0.25 0.25 1 N.T. 18 21 8 N.T. 19 0.5 0.25 2 N.T. 20 0.5 0.25 2 N.T. 21 4 32 >64.0 N.T. 22 0.50.5 2 N.T. 23 0.5 0.25 1 N.T. 24 0.5 0.25 2 N.T. 25 0.5 0.5 4 N.T. 260.5 0.125 2 N.T. 27 1 1 2 N.T. 28 2 0.5 4 N.T. 29 2 0.5 >64 N.T. 30 0.58 1 N.T. N.T. = Not Tested ¹Value represents average 2 MICdeterminations

Table 2 below shows several compounds of the invention compared tocefipime (a cephalosporin antibiotic indicated to treat bacterialinfections caused from Pseudomonas aeruginosa), imipenem (a carbapenemantibiotic used to treat infections caused by P. aeruginosa) andComparative Example A (example 23 in EP 0281289, published Sep. 7,1988).

TABLE 2 In vitro and In Vivo Comparison Against P. aeruginosa

RTI PD₅₀ vs. Pa 1091-05 Pa (mg/kg) 1091-05 (95% MIC confidence PaCompound Structure (R¹) (mg/mL) interval) MIC90² Cefepime — 2       22  64 Imipenem — 0.5     1.04 >64 Comarative —CH₃ 0.5  >150¹    1 ExampleA Example 15

0.5   >70.8    1 Example 6

0.125    32.7 (23.7-42.0)    1 Example 7

0.125    15.7 (8.45-22.96)    1 Example 3

0.125    20.6  (8.7-32.52)    1 Example 5

0.125    18.6 (8.94-28.29)    1 Example 4

0.125    25.0 (24.8-25.2)    1 ¹Data are from a previous experiment ²91clinical isolate

Table 2 shows the results for compounds of the invention which wereevaluated for efficacy in the murine respiratory tract infection modelagainst P. aeruginosa 1091-05. For this model, C3H/HeN mice wereimmunosuppressed with cyclophosphamide given orally at 150 mg/kg and 100mg/kg on days −4 and −1 relative to challenge, respectively. Mice wereanesthetized with isoflurane (5% in oxygen) and the bacterial inoculumwas given to each mouse via intranasal instillation in a 40 μL volume(˜2.8×10³ cfu per mouse). Mice were dosed with compound administered viasubcutaneous injection beginning at four hours post-challenge, andcontinuing for two days of BID therapy. Lethalities were followed overten days and the 50% protective doses (PD₅₀s) were determined. includeinterpretative comment on The known monocarbam prototype ComparativeExample A (example 23b in EP 0281289, published Sep. 7, 1988) typicallyhas a PD₅₀ of 100 mg/kg in this model. However, the exemplifiedmonocarbams of the present invention were evaluated in this model andmany demonstrated better efficacy than Comparative Example A, forexample, Example 4 (25.0 mg/kg), Example 6 (32.7 mg/kg), Example 5 (18.6mg/kg), Example 3 (20.6 mg/kg), and Example 7 (15.7 mg/kg).

PD₅₀ is a measure of the ability of a compound to protect mice from alethal infection. Hence, a lower value in this study is indicative ofimproved efficacy. Since the 95% confidence intervals (the range thatpredicts where the actual value will lie with 95% confidence) calculatedfor the compounds Example 3, Example 6, Example 4, Example 7 and Example5 do not overlap with the PD₅₀ value determined for Comparative ExampleA, it can be concluded that these compounds are significantly moreefficacious relative to Comparative Example A. This result wasunexpected given the similar MICs against the pathogen used (P.aeruginosa 1091-05). Importantly, performance in these pre-clinical invivo models is predictive of outcomes of clinical efficacy against thesetypes of infections.

1. A compound of formula (I),

or a pharmaceutically acceptable salt thereof, wherein R¹ is(C₁-C₆)alkyl substituted with an NR⁷R⁸; R² is hydrogen; R³ is hydrogen;R⁴ is methyl; R⁵ is methyl; R⁶ is —C(═O)OH; R⁷ and R⁸ are independently(C₁-C₆)alkyl; and X is C(H).
 2. A compound of formula (I),

or a pharmaceutically acceptable salt thereof, wherein R¹ is(C₁-C₆)alkyl substituted with —C(═O)NH₂, R² is hydrogen; R³ is hydrogen;R⁴ is methyl; R⁵ is methyl; R⁶ is —C(═O)OH; and X is C(H).
 3. A compoundof formula (IB):

wherein R¹ is selected from the group consisting of

or a pharmaceutically acceptable salt thereof.
 4. A compound of formula(IB):

wherein R¹ is selected from the group consisting of

or a pharmaceutically acceptable salt thereof.
 5. A compound of formula(IB):

wherein R¹ is selected from the group consisting of

or a pharmaceutically acceptable salt thereof.
 6. A compound of formula(IB):

wherein R¹ is selected from the group consisting of

or a pharmaceutically acceptable salt thereof.
 7. The pharmaceuticallyacceptable salt of a compound according to any one of claims 3 to 6,wherein said salt is a potassium or sodium salt.
 8. The pharmaceuticallyacceptable salt of a compound according to any one of claims 3 to 6wherein said salt is a bis-potassium or bis-sodium salt.
 9. Apharmaceutical composition comprising the compound of any one of claims3 to 6, or pharmaceutically acceptable salt thereof, and apharmaceutically acceptable carrier.
 10. A composition comprising acompound of formula (I),

or pharmaceutically acceptable salt thereof; wherein R¹ is (C₁-C₆)alkylsubstituted with 1 to 3 substituents selected from the group consistingof halo, hydroxy, (C₁-C₆)alkoxy, —NR⁷R⁸, —C(═O)NR⁷R⁸, and a 3 to 7membered heterocycle, wherein R⁷ and R⁸ are independently hydrogen or(C₁-C₆)alkyl, wherein said heterocycle contains 1 to 3 heteroatomsindependently selected from O, N, or S; R² is hydrogen or methyl; R³ ishydrogen or methyl; R⁴ is hydrogen, deuterium, or methyl optionallysubstituted with 1 to 3 substituents independently selected from F orCl; R⁵ is hydrogen, deuterium or methyl optionally substituted with 1 to3 substituents independently selected from F or Cl; R⁶ is H or —C(═O)OH;and X is C(H), C(F), C(Cl), or N, and an additional antibacterial agentselected from the group consisting of cefepime, ceftazidime, cefpirome,cefditoren pivoxil, cefoperazone, ceftazidime, cefdinir, cefotaxime,cefpodoxime, cephalothin, cefaclor, cefixime, cefotetan, imipenem,meropenem, ertapenem, doripenem, sulbactam, clavulanic acid, tazobactam,piperacillin, sulopenem, amikacin, gentamicin, kanamycin, neomycin,netilmicin, paromomycin, rhodostreptomycin, streptomycin, tobramycin,apramycin, polymyxin B, colistin, norfloxacin, ciprofloxacin,levofloxacin, moxifloxacin, enoxacin, amoxicillin, ampicillin,clindamycin, lincomycin, metronidazole, vancomycin, dalbavancin,telavancin, oritivancin, linezolid, daptomycin, tetracycline andtigecycline.
 11. The composition of claim 10, wherein said additionalantibacterial agent is selected from the group consisting of cefepime,ceftazidime, cefpirome, cefditoren pivoxil, cefoperazone, ceftazidime,cefdinir, cefotaxime, cefpodoxime, cephalothin, cefaclor, cefixime,cefotetan, imipenem, meropenem, ertapenem, doripenem, sulbactam,clavulanic acid, tazobactam, piperacillin, and sulopenem.
 12. Acomposition comprising a compound of formula (I),

or pharmaceutically acceptable salt thereof; wherein R¹ is (C₁-C₆)alkylsubstituted with 1 to 3 substituents selected from the group consistingof halo, hydroxy, (C₁-C₆)alkoxy, —NR⁷R⁸, —C(═O)NR⁷R⁸, and a 3 to 7membered heterocycle, wherein R⁷ and R⁸ are independently hydrogen or(C₁-C₆)alkyl, wherein said heterocycle contains 1 to 3 heteroatomsindependently selected from O, N, or S; R² is hydrogen or methyl; R³ ishydrogen or methyl; R⁴ is hydrogen, deuterium, or methyl optionallysubstituted with 1 to 3 substituents independently selected from F orCl; R⁵ is hydrogen, deuterium or methyl optionally substituted with 1 to3 substituents independently selected from F or Cl; R⁶ is H or —C(═O)OH;and X is C(H), C(F), C(Cl), or N, and an additional antibacterial agentselected from the group consisting of clindamycin, metronidazole,imipenem, meropenem, doripenem, ertapenem, cefotetan, cefepime, andcefpirome, or a third generation cephalosporin.
 13. The composition ofclaim 12 wherein the additional antibacterial agent is cefepime.
 14. Thecomposition of claim 12 wherein the additional antibacterial agent ismeropenem.
 15. The composition of claim 10 wherein said compound is

or a pharmaceutically acceptable salt thereof.
 16. The composition ofclaim 10 wherein said compound is

or pharmaceutically acceptable salt thereof.
 17. The composition ofclaim 10 wherein said compound is

or pharmaceutically acceptable salt thereof.
 18. The composition ofclaim 10 wherein said compound is

or pharmaceutically acceptable salt thereof.
 19. The composition ofclaim 10 wherein said compound is

or pharmaceutically acceptable salt thereof.
 20. The composition of anyone of claims 15 to 19 wherein said additional anti-bacterial agent iscefepime.
 21. The composition of any one of claims 15 to 19 wherein saidadditional anti-bacterial agent is meropenem.